changeset 946:cfe8f3917a71

red black tree insert done
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Mon, 17 Jun 2024 12:47:53 +0900
parents 7310dc7f2437
children 91137bc52ddd
files hoareBinaryTree1.agda hoareBinaryTree2.agda
diffstat 2 files changed, 639 insertions(+), 2438 deletions(-) [+]
line wrap: on
line diff
--- a/hoareBinaryTree1.agda	Mon Jun 17 08:24:11 2024 +0900
+++ b/hoareBinaryTree1.agda	Mon Jun 17 12:47:53 2024 +0900
@@ -40,7 +40,7 @@
 bt-depth (node key value t t₁) = suc (bt-depth t  ⊔ bt-depth t₁ )
 
 bt-ne : {n : Level} {A : Set n} {key : ℕ} {value : A} {t t₁ : bt A} → ¬ ( leaf ≡ node key value t t₁ )
-bt-ne {n} {A} {key} {value} {t} {t₁} () 
+bt-ne {n} {A} {key} {value} {t} {t₁} ()
 
 open import Data.Unit hiding ( _≟_ ) -- ;  _≤?_ ; _≤_)
 
@@ -258,7 +258,7 @@
 ti-property1 {n} {A} {key₁} {value₂} {.leaf} {.leaf} (t-single .key₁ .value₂) = ⟪ tt , tt ⟫
 ti-property1 {n} {A} {key₁} {value₂} {.leaf} {.(node key₂ _ _ _)} (t-right .key₁ key₂ x x₁ x₂ t) = ⟪ tt , ⟪ x , ⟪ x₁ , x₂ ⟫ ⟫ ⟫
 ti-property1 {n} {A} {key₁} {value₂} {.(node key _ _ _)} {.leaf} (t-left key .key₁ x x₁ x₂ t) = ⟪ ⟪ x , ⟪ x₁ , x₂ ⟫ ⟫ , tt ⟫
-ti-property1 {n} {A} {key₁} {value₂} {.(node key _ _ _)} {.(node key₂ _ _ _)} (t-node key .key₁ key₂ x x₁ x₂ x₃ x₄ x₅ t t₁) 
+ti-property1 {n} {A} {key₁} {value₂} {.(node key _ _ _)} {.(node key₂ _ _ _)} (t-node key .key₁ key₂ x x₁ x₂ x₃ x₄ x₅ t t₁)
      = ⟪ ⟪ x , ⟪ x₂ , x₃ ⟫ ⟫ , ⟪ x₁ , ⟪ x₄ , x₅ ⟫ ⟫ ⟫
 
 
@@ -955,10 +955,10 @@
 
 data RBI-state  {n : Level} {A : Set n} (key : ℕ) (value : A) : (tree repl : bt (Color ∧ A) ) → (stak : List (bt (Color ∧ A))) → Set n where
    rebuild : {tree repl : bt (Color ∧ A) } {stack : List (bt (Color ∧ A))} → color tree ≡ color repl → black-depth repl ≡ black-depth tree
-       → ¬ ( tree ≡ leaf) 
+       → ¬ ( tree ≡ leaf)
        → (rotated : replacedRBTree key value tree repl)
        → RBI-state key value tree repl stack  -- one stage up
-   rotate  : (tree : bt (Color ∧ A)) → {repl : bt (Color ∧ A) } {stack : List (bt (Color ∧ A))} → color repl ≡ Red 
+   rotate  : (tree : bt (Color ∧ A)) → {repl : bt (Color ∧ A) } {stack : List (bt (Color ∧ A))} → color repl ≡ Red
        → (rotated : replacedRBTree key value tree repl)
        → RBI-state key value tree repl stack  -- two stages up
    top-black : {tree repl : bt (Color ∧ A) } → {stack : List (bt (Color ∧ A))}  → stack ≡ tree ∷ []
@@ -1020,26 +1020,67 @@
         suc (black-depth right) ∎ ) ⟫ where open ≡-Reasoning
 black-children-eq {n} {A} {tree} {left} {right} {key} {value} {Red} eq () rb
 
-black-depth-cong  : {n : Level} (A : Set n)  {tree tree₁ : bt (Color ∧ A)} 
+black-depth-cong  : {n : Level} (A : Set n)  {tree tree₁ : bt (Color ∧ A)}
    → tree ≡ tree₁ → black-depth tree ≡ black-depth tree₁
 black-depth-cong  {n} A  {leaf} {leaf} refl = refl
-black-depth-cong {n} A {node key ⟪ Red , value ⟫ left right} {node .key ⟪ Red , .value ⟫ .left .right} refl 
+black-depth-cong {n} A {node key ⟪ Red , value ⟫ left right} {node .key ⟪ Red , .value ⟫ .left .right} refl
    = cong₂ (λ j k → j ⊔ k ) (black-depth-cong A {left} {left} refl) (black-depth-cong A {right} {right} refl)
-black-depth-cong {n} A {node key ⟪ Black , value ⟫ left right} {node .key ⟪ Black , .value ⟫ .left .right} refl 
+black-depth-cong {n} A {node key ⟪ Black , value ⟫ left right} {node .key ⟪ Black , .value ⟫ .left .right} refl
    = cong₂ (λ j k → suc (j ⊔ k) ) (black-depth-cong A {left} {left} refl) (black-depth-cong A {right} {right} refl)
 
-rbi-from-red-black : {n : Level } {A : Set n} → (n1 rp-left : bt (Color ∧ A)) → (kp : ℕ) → (vp : Color ∧ A) 
+black-depth-resp  : {n : Level} (A : Set n)   (tree tree₁ : bt (Color ∧ A)) → {c1 c2 : Color}  { l1 l2 r1 r2 : bt (Color ∧ A)} {key1 key2 : ℕ} {value1 value2 : A}
+   → tree ≡ node key1 ⟪ c1 , value1 ⟫ l1 r1 → tree₁ ≡ node key2 ⟪ c2 , value2 ⟫ l2 r2
+   → color tree  ≡ color tree₁
+   → black-depth l1 ≡ black-depth l2 → black-depth r1 ≡ black-depth r2
+   → black-depth tree ≡ black-depth tree₁
+black-depth-resp  A _ _ {Black} {Black} refl refl refl eql eqr = cong₂ (λ j k → suc (j ⊔ k) ) eql eqr
+black-depth-resp  A _ _ {Red} {Red} refl refl refl eql eqr = cong₂ (λ j k → j ⊔ k ) eql eqr
+
+red-children-eq1 : {n : Level} {A : Set n}  {tree left right : bt (Color ∧ A)} → {key : ℕ} → {value : A} → {c : Color}
+   → tree ≡ node key ⟪ c , value ⟫ left right
+   → color tree ≡ Red
+   → RBtreeInvariant tree
+   → (black-depth tree ≡ black-depth left ) ∧ (black-depth tree ≡ black-depth right)
+red-children-eq1 {n} {A} {.(node key₁ ⟪ Red , value₁ ⟫ left right)} {left} {right} {.key₁} {.value₁} {Red} refl eq₁ rb2@(rb-red key₁ value₁ x x₁ x₂ rb rb₁) =
+  ⟪ ( begin
+        black-depth left ⊔ black-depth right ≡⟨ cong (λ k → black-depth left ⊔ k) (sym (RBtreeEQ rb2)) ⟩
+        black-depth left ⊔ black-depth left ≡⟨ ⊔-idem _ ⟩
+        black-depth left ∎  ) ,  (
+     begin
+        black-depth left ⊔ black-depth right ≡⟨ cong (λ k → k ⊔ black-depth right ) (RBtreeEQ rb2) ⟩
+        black-depth right ⊔ black-depth right ≡⟨ ⊔-idem _ ⟩
+        black-depth right ∎ ) ⟫ where open ≡-Reasoning
+red-children-eq1 {n} {A} {.(node key ⟪ Black , value ⟫ left right)} {left} {right} {key} {value} {Black} refl () rb
+
+black-children-eq1 : {n : Level} {A : Set n}  {tree left right : bt (Color ∧ A)} → {key : ℕ} → {value : A} → {c : Color}
+   → tree ≡ node key ⟪ c , value ⟫ left right
+   → color tree ≡ Black
+   → RBtreeInvariant tree
+   → (black-depth tree ≡ suc (black-depth left) ) ∧ (black-depth tree ≡ suc (black-depth right))
+black-children-eq1 {n} {A} {.(node key₁ ⟪ Black , value₁ ⟫ left right)} {left} {right} {.key₁} {.value₁} {Black} refl eq₁ rb2@(rb-black key₁ value₁ x rb rb₁) =
+  ⟪ ( begin
+        suc (black-depth left ⊔ black-depth right) ≡⟨ cong (λ k → suc (black-depth left ⊔ k)) (sym (RBtreeEQ rb2)) ⟩
+        suc (black-depth left ⊔ black-depth left) ≡⟨ ⊔-idem _ ⟩
+        suc (black-depth left) ∎  ) ,  (
+     begin
+        suc (black-depth left ⊔ black-depth right) ≡⟨ cong (λ k → suc (k ⊔ black-depth right)) (RBtreeEQ rb2) ⟩
+        suc (black-depth right ⊔ black-depth right) ≡⟨ ⊔-idem _ ⟩
+        suc (black-depth right) ∎ ) ⟫ where open ≡-Reasoning
+black-children-eq1 {n} {A} {.(node key ⟪ Red , value ⟫ left right)} {left} {right} {key} {value} {Red} refl () rb
+
+
+rbi-from-red-black : {n : Level } {A : Set n} → (n1 rp-left : bt (Color ∧ A)) → (kp : ℕ) → (vp : Color ∧ A)
     → RBtreeInvariant n1 → RBtreeInvariant rp-left
     → black-depth n1 ≡ black-depth rp-left
     → color n1 ≡ Black → color rp-left ≡ Black →  ⟪ Red , proj2 vp ⟫ ≡ vp
     → RBtreeInvariant (node kp vp n1 rp-left)
-rbi-from-red-black leaf leaf kp vp rb1 rbp deq ceq1 ceq2 ceq3 
+rbi-from-red-black leaf leaf kp vp rb1 rbp deq ceq1 ceq2 ceq3
     = subst (λ k → RBtreeInvariant (node kp k leaf leaf)) ceq3 (rb-red kp (proj2 vp)  refl refl refl rb-leaf rb-leaf)
-rbi-from-red-black leaf (node key ⟪ .Black , proj3 ⟫ trpl trpl₁) kp vp rb1 rbp deq ceq1 refl ceq3 
+rbi-from-red-black leaf (node key ⟪ .Black , proj3 ⟫ trpl trpl₁) kp vp rb1 rbp deq ceq1 refl ceq3
     = subst (λ k → RBtreeInvariant (node kp k _ _)) ceq3 (rb-red kp (proj2 vp) refl refl deq rb1 rbp)
-rbi-from-red-black (node key ⟪ .Black , proj3 ⟫ tn1 tn2) leaf kp vp rb1 rbp deq refl ceq2 ceq3 
+rbi-from-red-black (node key ⟪ .Black , proj3 ⟫ tn1 tn2) leaf kp vp rb1 rbp deq refl ceq2 ceq3
     = subst (λ k → RBtreeInvariant (node kp k _ _)) ceq3 (rb-red kp (proj2 vp) refl refl deq rb1 rbp)
-rbi-from-red-black (node key ⟪ .Black , proj3 ⟫ tn1 tn2) (node key₁ ⟪ .Black , proj4 ⟫ trpl trpl₁) kp vp rb1 rbp deq refl refl ceq3 
+rbi-from-red-black (node key ⟪ .Black , proj3 ⟫ tn1 tn2) (node key₁ ⟪ .Black , proj4 ⟫ trpl trpl₁) kp vp rb1 rbp deq refl refl ceq3
   = subst (λ k → RBtreeInvariant (node kp k _ _)) ceq3 (rb-red kp (proj2 vp) refl refl deq rb1 rbp )
 
 ⊔-succ : {m n : ℕ} → suc (m ⊔ n) ≡ suc m ⊔ suc n
@@ -1277,43 +1318,43 @@
 RB-repl→ti (node key₂ ⟪ Black , _ ⟫ (node key₁ ⟪ Red , _ ⟫ t₀ leaf) (node key₃ ⟪ c1 , v1 ⟫ left right)) (node key₂ ⟪ Red , value₁ ⟫ (node _ ⟪ Black , value₂ ⟫ (node key₄ value₃ t t₁) .leaf) (node key₃ ⟪ Black , v1 ⟫ left right)) key value (t-node _ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-ll x y lt trb) = t-node _ _ _ x₁ x₂ ⟪ <-trans (proj1 rr00) x₁  , ⟪ >-tr< (proj1 (proj2 rr00)) x₁ , >-tr< (proj2 (proj2 rr00)) x₁ ⟫ ⟫ tt x₅ x₆ (t-left _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ (treeLeftDown _ _ ti) trb)) (replaceTree1 _ _ _ ti₁) where
         rr00 : (key₄ < key₁) ∧ tr< key₁ t ∧ tr< key₁ t₁
         rr00 = RB-repl→ti< _ _ _ _ _ trb lt (proj1 (ti-property1 ti))
-RB-repl→ti (node key₂ ⟪ Black , _ ⟫ (node key₁ ⟪ Red , _ ⟫ .leaf (node key₄ value₃ t₁ t₂)) (node key₃ ⟪ c0 , v1 ⟫ left right)) (node key₂ ⟪ Red , value₁ ⟫ (node _ ⟪ Black , value₂ ⟫ (node key₅ value₄ t t₃) .(node key₄ value₃ t₁ t₂)) (node key₃ ⟪ Black , v1 ⟫ left right)) key value (t-node _ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-right .key₁ .key₄ x₇ x₈ x₉ ti) ti₁) (rbr-flip-ll x y lt trb) 
+RB-repl→ti (node key₂ ⟪ Black , _ ⟫ (node key₁ ⟪ Red , _ ⟫ .leaf (node key₄ value₃ t₁ t₂)) (node key₃ ⟪ c0 , v1 ⟫ left right)) (node key₂ ⟪ Red , value₁ ⟫ (node _ ⟪ Black , value₂ ⟫ (node key₅ value₄ t t₃) .(node key₄ value₃ t₁ t₂)) (node key₃ ⟪ Black , v1 ⟫ left right)) key value (t-node _ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-right .key₁ .key₄ x₇ x₈ x₉ ti) ti₁) (rbr-flip-ll x y lt trb)
     = t-node _ _ _ x₁ x₂ ⟪ <-trans (proj1 rr00) x₁ , ⟪ >-tr< (proj1 (proj2 rr00)) x₁  , >-tr< (proj2 (proj2 rr00)) x₁  ⟫ ⟫  x₄ x₅ x₆ (t-node _ _ _ (proj1 rr00) x₇ (proj1 (proj2 rr00)) (proj2 (proj2 (rr00))) x₈ x₉ (RB-repl→ti _ _ _ _ t-leaf trb) ti) (replaceTree1 _ _ _ ti₁) where
         rr00 : (key₅ < key₁) ∧ tr< key₁ t ∧ tr< key₁ t₃
         rr00 = RB-repl→ti< _ _ _ _ _ trb lt tt
-RB-repl→ti (node key₂ ⟪ Black , _ ⟫ (node key₁ ⟪ Red , _ ⟫ .(node key₆ _ _ _) (node key₄ value₃ t₁ t₂)) (node key₃ ⟪ c0 , v1 ⟫ left right)) (node key₂ ⟪ Red , value₁ ⟫ (node _ ⟪ Black , value₂ ⟫ (node key₅ value₄ t t₃) .(node key₄ value₃ t₁ t₂)) (node key₃ ⟪ Black , v1 ⟫ left right)) key value (t-node _ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-node key₆ .key₁ .key₄ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti ti₂) ti₁) (rbr-flip-ll x y lt trb) 
-   = t-node _ _ _ x₁ x₂  ⟪ <-trans (proj1 rr00) x₁ , ⟪ >-tr< (proj1 (proj2 rr00)) x₁ , >-tr< (proj2 (proj2 rr00)) x₁ ⟫ ⟫  
+RB-repl→ti (node key₂ ⟪ Black , _ ⟫ (node key₁ ⟪ Red , _ ⟫ .(node key₆ _ _ _) (node key₄ value₃ t₁ t₂)) (node key₃ ⟪ c0 , v1 ⟫ left right)) (node key₂ ⟪ Red , value₁ ⟫ (node _ ⟪ Black , value₂ ⟫ (node key₅ value₄ t t₃) .(node key₄ value₃ t₁ t₂)) (node key₃ ⟪ Black , v1 ⟫ left right)) key value (t-node _ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-node key₆ .key₁ .key₄ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti ti₂) ti₁) (rbr-flip-ll x y lt trb)
+   = t-node _ _ _ x₁ x₂  ⟪ <-trans (proj1 rr00) x₁ , ⟪ >-tr< (proj1 (proj2 rr00)) x₁ , >-tr< (proj2 (proj2 rr00)) x₁ ⟫ ⟫
      x₄ x₅ x₆ (t-node _ _ _ (proj1 rr00) x₈ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) x₁₁ x₁₂ (RB-repl→ti _ _ _ _ ti trb) ti₂) (replaceTree1 _ _ _ ti₁) where
-        rr00 : (key₅ < key₁) ∧ tr< key₁ t ∧ tr< key₁ t₃ 
+        rr00 : (key₅ < key₁) ∧ tr< key₁ t ∧ tr< key₁ t₃
         rr00 = RB-repl→ti< _ _ _ _ _ trb lt ⟪ x₇ , ⟪ x₉ , x₁₀ ⟫ ⟫
 RB-repl→ti (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ left right) leaf) (node key₂ ⟪ Red , v1 ⟫ (node key₃ ⟪ Black , v2 ⟫ left right₁) leaf) key value
-      (t-left _ _ x₁ x₂ x₃ ti) (rbr-flip-lr x () lt lt2 trb) 
-RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ leaf leaf) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .leaf (node key₄ value₁ t₄ t₅)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-lr x y lt lt2 trb) 
+      (t-left _ _ x₁ x₂ x₃ ti) (rbr-flip-lr x () lt lt2 trb)
+RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ leaf leaf) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .leaf (node key₄ value₁ t₄ t₅)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-lr x y lt lt2 trb)
   = t-node _ _ _ x₁ x₂ tt rr00 x₅ x₆ (t-right _ _ (proj1 rr01) (proj1 (proj2 rr01)) (proj2 (proj2 rr01)) (RB-repl→ti _ _ _ _ t-leaf trb)) (replaceTree1 _ _ _ ti₁) where
        rr00 : (key₄ < key₁) ∧ tr< key₁ t₄ ∧ tr< key₁ t₅
-       rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 tt 
+       rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 tt
        rr01 : (key₂ < key₄) ∧ tr> key₂ t₄ ∧ tr> key₂ t₅
-       rr01 = RB-repl→ti> _ _ _ _ _ trb lt tt 
+       rr01 = RB-repl→ti> _ _ _ _ _ trb lt tt
 RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ leaf (node key₅ value₂ t₁ t₆)) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .leaf (node key₄ value₁ t₄ t₅)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-right .key₂ .key₅ x₇ x₈ x₉ ti) ti₁) (rbr-flip-lr x y lt lt2 trb) = t-node _ _ _ x₁ x₂ tt rr00 x₅ x₆ (t-right _ _ (proj1 rr01) (proj1 (proj2 rr01)) (proj2 (proj2 rr01)) (RB-repl→ti _ _ _ _ ti trb)) (replaceTree1 _ _ _ ti₁) where
        rr00 : (key₄ < key₁) ∧ tr< key₁ t₄ ∧ tr< key₁ t₅
        rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 x₄
        rr01 : (key₂ < key₄) ∧ tr> key₂ t₄ ∧ tr> key₂ t₅
        rr01 = RB-repl→ti> _ _ _ _ _ trb lt ⟪ x₇ , ⟪ x₈ , x₉ ⟫ ⟫
-RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ (node key₄ value₁ t t₅) .leaf) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .(node key₄ value₁ t t₅) (node key₅ value₂ t₄ t₆)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-left .key₄ .key₂ x₇ x₈ x₉ ti) ti₁) (rbr-flip-lr x y lt lt2 trb) 
+RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ (node key₄ value₁ t t₅) .leaf) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .(node key₄ value₁ t t₅) (node key₅ value₂ t₄ t₆)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-left .key₄ .key₂ x₇ x₈ x₉ ti) ti₁) (rbr-flip-lr x y lt lt2 trb)
     = t-node _ _ _ x₁ x₂ x₃ rr00 x₅ x₆ (t-node _ _ _ x₇ (proj1 rr01) x₈ x₉ (proj1 (proj2 rr01)) (proj2 (proj2 rr01)) ti (RB-repl→ti _ _ _ _ t-leaf trb)) (replaceTree1 _ _ _ ti₁) where
        rr00 : (key₅ < key₁) ∧ tr< key₁ t₄ ∧ tr< key₁ t₆
        rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 tt
        rr01 : (key₂ < key₅) ∧ tr> key₂ t₄ ∧ tr> key₂ t₆
        rr01 = RB-repl→ti> _ _ _ _ _ trb lt tt
-RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ (node key₄ value₁ t t₅) .(node key₆ _ _ _)) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .(node key₄ value₁ t t₅) (node key₅ value₂ t₄ t₆)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-node .key₄ .key₂ key₆ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti ti₂) ti₁) (rbr-flip-lr x y lt lt2 trb) 
+RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ (node key₄ value₁ t t₅) .(node key₆ _ _ _)) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ .(node key₄ value₁ t t₅) (node key₅ value₂ t₄ t₆)) .(to-black (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-node .key₄ .key₂ key₆ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti ti₂) ti₁) (rbr-flip-lr x y lt lt2 trb)
     = t-node _ _ _ x₁ x₂ x₃ rr00 x₅ x₆ (t-node _ _ _ x₇ (proj1 rr01) x₉ x₁₀ (proj1 (proj2 rr01)) (proj2 (proj2 rr01)) ti (RB-repl→ti _ _ _ _ ti₂ trb)) (replaceTree1 _ _ _ ti₁) where
         rr00 : (key₅ < key₁) ∧ tr< key₁ t₄ ∧ tr< key₁ t₆
         rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 x₄
         rr01 : (key₂ < key₅) ∧ tr> key₂ t₄ ∧ tr> key₂ t₆
         rr01 = RB-repl→ti> _ _ _ _ _ trb lt ⟪ x₈ , ⟪ x₁₁ , x₁₂ ⟫ ⟫
 RB-repl→ti (node _ ⟪ Black , _ ⟫ leaf (node _ ⟪ Red , _ ⟫ t t₁)) (node key₁ ⟪ Red , v1 ⟫ .(to-black leaf) (node key₂ ⟪ Black , v2 ⟫ t₂ t₁)) key value
-      (t-right _ _ x₁ x₂ x₃ ti) (rbr-flip-rl x () lt lt2 trb) 
-RB-repl→ti (node _ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node _ ⟪ Red , v3 ⟫ t₂ leaf)) (node key₁ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , v2 ⟫ t t₁)) (node key₃ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) .leaf)) key value (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-rl x y lt lt2 trb) 
+      (t-right _ _ x₁ x₂ x₃ ti) (rbr-flip-rl x () lt lt2 trb)
+RB-repl→ti (node _ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node _ ⟪ Red , v3 ⟫ t₂ leaf)) (node key₁ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , v2 ⟫ t t₁)) (node key₃ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) .leaf)) key value (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-rl x y lt lt2 trb)
    = t-node _ _ _ x₁ x₂ x₃ x₄ rr00 tt (replaceTree1 _ _ _ ti) (t-left _ _ (proj1 rr01) (proj1 (proj2 rr01)) (proj2 (proj2 rr01)) (RB-repl→ti _ _ _ _ (treeLeftDown _ _ ti₁) trb)) where
         rr00 : (key₁ < key₄) ∧ tr> key₁ t₄ ∧ tr> key₁ t₅
         rr00 = RB-repl→ti> _ _ _ _ _ trb lt x₅
@@ -1326,7 +1367,7 @@
         rr01 = RB-repl→ti< _ _ _ _ _ trb lt2 tt
         rr02 : (key₁ < key₅) ∧ tr> key₁ t₃ ∧ tr> key₁ t₆
         rr02 = ⟪ <-trans x₂ x₇ , ⟪ <-tr> x₈ x₂  , <-tr> x₉ x₂ ⟫ ⟫
-RB-repl→ti (node _ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node _ ⟪ Red , v3 ⟫ .(node key₆ _ _ _) (node key₅ value₂ t₃ t₆))) (node key₁ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , v2 ⟫ t t₁)) (node key₃ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) .(node key₅ value₂ t₃ t₆))) key value (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-node key₆ .key₃ .key₅ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti₁ ti₂)) (rbr-flip-rl x y lt lt2 trb) 
+RB-repl→ti (node _ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node _ ⟪ Red , v3 ⟫ .(node key₆ _ _ _) (node key₅ value₂ t₃ t₆))) (node key₁ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , v2 ⟫ t t₁)) (node key₃ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) .(node key₅ value₂ t₃ t₆))) key value (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-node key₆ .key₃ .key₅ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti₁ ti₂)) (rbr-flip-rl x y lt lt2 trb)
    = t-node _ _ _ x₁ x₂ x₃ x₄ rr00 rr02 (replaceTree1 _ _ _ ti) (t-node _ _ _ (proj1 rr01) x₈ (proj1 (proj2 rr01))  (proj2 (proj2 rr01))  x₁₁ x₁₂ (RB-repl→ti _ _ _ _ ti₁ trb) ti₂) where
         rr00 : (key₁ < key₄) ∧ tr> key₁ t₄ ∧ tr> key₁ t₅
         rr00 = RB-repl→ti> _ _ _ _ _ trb lt x₅
@@ -1335,11 +1376,11 @@
         rr02 : (key₁ < key₅) ∧ tr> key₁ t₃ ∧ tr> key₁ t₆
         rr02 = ⟪ proj1 x₆ , ⟪  <-tr> x₁₁ x₂ , <-tr> x₁₂ x₂  ⟫ ⟫
 RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ leaf (node key₂ ⟪ Red , v2 ⟫ t t₁)) (node _ ⟪ Red , _ ⟫ .(to-black leaf) (node _ ⟪ Black , v2 ⟫ t t₂)) key value
-    (t-right _ _ x₁ x₂ x₃ ti) (rbr-flip-rr x () lt trb) 
+    (t-right _ _ x₁ x₂ x₃ ti) (rbr-flip-rr x () lt trb)
 RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node key₃ ⟪ Red , c3 ⟫ leaf t₃)) (node _ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , v2 ⟫ t t₁)) (node _ ⟪ Black , c3 ⟫ .leaf (node key₄ value₁ t₄ t₅))) key value (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-rr x y lt trb) = t-node _ _ _ x₁ x₂ x₃ x₄ x₅ rr01 (replaceTree1 _ _ _ ti) (t-right _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ (treeRightDown _ _ ti₁) trb)) where
         rr00 : (key₃ < key₄) ∧ tr> key₃ t₄ ∧ tr> key₃ t₅
         rr00 = RB-repl→ti> _ _ _ _ _ trb lt (proj2 (ti-property1 ti₁))
-        rr01 : (key₁ < key₄) ∧ tr> key₁ t₄ ∧ tr> key₁ t₅ 
+        rr01 : (key₁ < key₄) ∧ tr> key₁ t₄ ∧ tr> key₁ t₅
         rr01 = RB-repl→ti> _ _ _ _ _ trb (<-trans x₂ lt) x₆
 RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node key₃ ⟪ Red , c3 ⟫ (node key₄ value₁ t₂ t₅) .leaf)) (node _ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , v2 ⟫ t t₁)) (node _ ⟪ Black , c3 ⟫ .(node key₄ value₁ t₂ t₅) (node key₅ value₂ t₄ t₆))) key value (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-left .key₄ .key₃ x₇ x₈ x₉ ti₁)) (rbr-flip-rr x y lt trb) = t-node _ _ _ x₁ x₂ x₃ x₄ x₅ rr02 (replaceTree1 _ _ _ ti) (t-node _ _ _ x₇ (proj1 rr00) x₈ x₉ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ti₁ (RB-repl→ti _ _ _ _ t-leaf trb)) where
         rr00 : (key₃ < key₅) ∧ tr> key₃ t₄ ∧ tr> key₃ t₆
@@ -1814,16 +1855,16 @@
  → (tree1 : bt (Color ∧ A))
  → (stack : List (bt (Color ∧ A)))
  → stackInvariant key tree1 tree0 stack
- → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key ) 
+ → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )
  → (exit : (stack : List ( bt (Color ∧ A))) (r : RBI key value tree0 stack ) → t ) → t
 createRBT {n} {m} {A} {t} key value orig rbi ti tree (x ∷ []) si P exit = crbt00 orig P refl where
      crbt00 : (tree1 : bt (Color ∧ A)) → (tree ≡ leaf ) ∨ ( node-key tree ≡ just key ) → tree1 ≡ orig → t
-     crbt00 leaf P refl = exit (x ∷ []) record {  
+     crbt00 leaf P refl = exit (x ∷ []) record {
          tree = leaf
          ; repl = node key ⟪ Red , value ⟫ leaf leaf
          ; origti = ti
          ; origrb = rbi
-         ; treerb = rb-leaf 
+         ; treerb = rb-leaf
          ; replrb = rb-red key value refl refl refl rb-leaf rb-leaf
          ; si = subst (λ k → stackInvariant key k leaf _ ) crbt01 si
          ; state = rotate leaf refl rbr-leaf
@@ -1834,16 +1875,16 @@
      crbt00 (node key₁ value₁ left right ) (case1 eq) refl with si-property-last _ _ _ _ si | si-property1 si
      ... | refl | refl = ⊥-elim (bt-ne (sym eq))
      crbt00 (node key₁ value₁ left right ) (case2 eq) refl with si-property-last _ _ _ _ si | si-property1 si
-     ... | refl | refl = exit (x ∷ []) record {  
+     ... | refl | refl = exit (x ∷ []) record {
          tree = node key₁ value₁ left right
-         ; repl = node key₁ ⟪ proj1 value₁ , value ⟫ left right 
+         ; repl = node key₁ ⟪ proj1 value₁ , value ⟫ left right
          ; origti = ti
          ; origrb = rbi
          ; treerb = rbi
          ; replrb = crbt03 value₁ rbi
          ; si = si
          ; state = rebuild refl (crbt01 value₁ ) (λ ()) crbt04
-         }  where 
+         }  where
              crbt01 : (value₁ : Color ∧ A) → black-depth (node key₁ ⟪ proj1 value₁ , value ⟫ left right) ≡ black-depth (node key₁ value₁ left right)
              crbt01 ⟪ Red , proj4 ⟫ = refl
              crbt01 ⟪ Black , proj4 ⟫ = refl
@@ -1857,7 +1898,7 @@
 createRBT {n} {m} {A} {t} key value orig rbi ti tree (x ∷ leaf ∷ stack) si P exit = ⊥-elim (si-property-parent-node _ _ _ si refl)
 createRBT {n} {m} {A} {t} key value orig rbi ti tree sp@(x ∷ node kp vp pleft pright ∷ stack) si P exit = crbt00 tree P refl where
      crbt00 : (tree1 : bt (Color ∧ A)) → (tree ≡ leaf ) ∨ ( node-key tree ≡ just key ) → tree1 ≡ tree → t
-     crbt00 leaf P refl = exit sp record {  
+     crbt00 leaf P refl = exit sp record {
          tree = leaf
          ; repl = node key ⟪ Red , value ⟫ leaf leaf
          ; origti = ti
@@ -1866,19 +1907,19 @@
          ; replrb = rb-red key value refl refl refl rb-leaf rb-leaf
          ; si = si
          ; state = rotate leaf refl rbr-leaf
-         } 
+         }
      crbt00 (node key₁ value₁ left right ) (case1 eq) refl = ⊥-elim (bt-ne (sym eq))
      crbt00 (node key₁ value₁ left right ) (case2 eq) refl with si-property-last _ _ _ _ si | si-property1 si
-     ... | eq1 | eq2 = exit sp record {  
+     ... | eq1 | eq2 = exit sp record {
          tree = node key₁ value₁ left right
-         ; repl = node key₁ ⟪ proj1 value₁ , value ⟫ left right 
+         ; repl = node key₁ ⟪ proj1 value₁ , value ⟫ left right
          ; origti = ti
          ; origrb = rbi
          ; treerb = treerb
          ; replrb = crbt03 value₁ treerb
          ; si = si
          ; state = rebuild refl (crbt01 value₁ ) (λ ()) crbt04
-         }  where 
+         }  where
              crbt01 : (value₁ : Color ∧ A) → black-depth (node key₁ ⟪ proj1 value₁ , value ⟫ left right) ≡ black-depth (node key₁ value₁ left right)
              crbt01 ⟪ Red , proj4 ⟫ = refl
              crbt01 ⟪ Black , proj4 ⟫ = refl
@@ -1991,7 +2032,7 @@
        rb07 : ( color repl ≡ Red ) ∨ (color (RBI.tree r) ≡ color repl) → t
        rb07 (case2 cc ) = exit  (orig ∷ []) refl record {
          tree = orig
-         ; repl = node key₁ value₁ left repl 
+         ; repl = node key₁ value₁ left repl
          ; origti = RBI.origti r
          ; origrb = RBI.origrb r
          ; treerb = RBI.origrb r
@@ -2040,7 +2081,7 @@
               ; state = rebuild (cong color x) rb06 (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))  (subst (λ k → replacedRBTree key value k rb01) (sym x) (rbr-left ceq rb04 rot))
              } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
                rb01 : bt (Color ∧ A)
-               rb01 = node kp vp repl n1 
+               rb01 = node kp vp repl n1
                rb03 : black-depth n1 ≡ black-depth repl
                rb03 = trans (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)))) (RB-repl→eq _ _ (RBI.treerb r) rot)
                rb02 : RBtreeInvariant rb01
@@ -2099,7 +2140,7 @@
              } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
                rb01 : bt (Color ∧ A)
                rb01 = node kp vp repl n1
-               rb03 : black-depth n1 ≡ black-depth repl 
+               rb03 : black-depth n1 ≡ black-depth repl
                rb03 = trans (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)))) ((RB-repl→eq _ _ (RBI.treerb r) rot))
                rb02 : RBtreeInvariant rb01
                rb02 with subst (λ k → RBtreeInvariant k) x (treerb pg)
@@ -2226,8 +2267,8 @@
                black-depth n1 ⊔ black-depth n1 ≡⟨ cong (λ k → black-depth n1 ⊔ k) rb19 ⟩
                black-depth n1 ⊔ black-depth (PG.uncle pg) ∎ where open ≡-Reasoning
             rb17 : suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg))) ≡ black-depth (PG.grand pg)
-            rb17 = begin 
-                suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg))) 
+            rb17 = begin
+                suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg)))
                      ≡⟨ cong₂ (λ j k → suc (black-depth j ⊔ k)) eq (sym rb18) ⟩
                 suc (black-depth repl ⊔ black-depth repl) ≡⟨ ⊔-idem _ ⟩
                 suc (black-depth repl ) ≡⟨ cong suc (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
@@ -2235,6 +2276,7 @@
                 suc (black-depth (PG.parent pg) ) ≡⟨ sym (proj1 (black-children-eq refl (cong proj1 (sym rb14)) (subst (λ k → RBtreeInvariant k) x₁ rb02))) ⟩
                 black-depth (node kg vg (PG.parent pg) (PG.uncle pg)) ≡⟨ cong black-depth (sym x₁) ⟩
                 black-depth (PG.grand pg) ∎ where open ≡-Reasoning
+                -- outer case, repl  is not decomposed
                 -- lt          : key < kp
                 -- x           : PG.parent pg ≡ node kp vp (RBI.tree r) n1
                 -- x₁          : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
@@ -2249,8 +2291,9 @@
             ; treerb = rb02
             ; replrb = rb10
             ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-            ; state = rebuild (trans (cong color x₁) (cong proj1 (sym rb14))) rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
+            ; state = rebuild rb33 rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
            } rb15 where
+                -- inner case, repl  is decomposed
                 -- lt          : kp < key
                 -- x           : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
                 -- x₁          : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
@@ -2260,8 +2303,8 @@
             rb04 : kp < key
             rb04 = lt
             rb21 : key < kg   -- this can be a part of ParentGand relation
-            rb21 = si-property-< (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r) 
-                 (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)))) 
+            rb21 = si-property-< (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r)
+                 (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))))
                  (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
             rb16 : color n1 ≡ Black
             rb16 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
@@ -2271,20 +2314,22 @@
             rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
             rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case1 pcolor)
             ... | refl = refl
-            rb23 :  vr ≡ ⟪ Red , proj2 vr ⟫ 
+            rb33 : color (PG.grand pg) ≡ Black
+            rb33 = subst (λ k → color k ≡ Black ) (sym x₁) (sym (cong proj1 rb14))
+            rb23 :  vr ≡ ⟪ Red , proj2 vr ⟫
             rb23 with subst (λ k → color k ≡ Red ) (sym eq) repl-red
             ... | refl = refl
             rb20 : color rp-right ≡ Black
             rb20 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r) ) (cong proj1 rb23))
             rb03 : replacedRBTree key value (node kg _ (node kp _ n1 (RBI.tree r)) (PG.uncle pg))
                (node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫  n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)))
-            rb03 = rbr-rotate-lr rp-left rp-right kg kp rkey rb20 rb04 rb21  
+            rb03 = rbr-rotate-lr rp-left rp-right kg kp rkey rb20 rb04 rb21
                 (subst (λ k → replacedRBTree key value (RBI.tree r) k) (trans (sym eq) (cong (λ k → node rkey k rp-left rp-right) rb23 )) rot )
             rb24 : node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r)) (PG.uncle pg) ≡ PG.grand pg
             rb24 = trans (trans (cong₂ (λ j k → node kg j (node kp k n1 (RBI.tree r)) (PG.uncle pg)) rb14 rb13 ) (cong (λ k → node kg vg k (PG.uncle pg)) (sym x))) (sym x₁)
             rb25 : node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)) ≡ rb01
-            rb25 = begin 
-                node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)) 
+            rb25 = begin
+                node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg))
                      ≡⟨ cong (λ k → node _ _ (node kp k  n1 rp-left) _ ) rb13 ⟩
                 node rkey ⟪ Black , proj2 vr ⟫ (node kp vp n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg))  ≡⟨ refl  ⟩
                 rb01 ∎ where open ≡-Reasoning
@@ -2298,55 +2343,229 @@
             rb26 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
             rb28 : RBtreeInvariant rp-right
             rb28 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
+            rb31 : RBtreeInvariant (node rkey vr rp-left rp-right )
+            rb31 = subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)
             rb18 : black-depth rp-right ≡ black-depth (PG.uncle pg)
             rb18 = begin
-                black-depth rp-right ≡⟨ sym (proj2 (red-children-eq (cong (λ k → node rkey k rp-left rp-right) rb23) 
-                     refl (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)) )) ⟩
-                black-depth (node rkey vr rp-left rp-right) ≡⟨ cong black-depth eq ⟩
+                black-depth rp-right ≡⟨ sym ( proj2 (red-children-eq1 (sym eq) repl-red (RBI.replrb r) )) ⟩
                 black-depth (RBI.repl r) ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                black-depth (RBI.tree r) ≡⟨ sym (proj2 (red-children-eq refl refl 
-                   (subst (λ k → RBtreeInvariant k) (trans x (cong (λ k → node kp k n1 (RBI.tree r) ) (sym rb13) )) rb09))) ⟩
-                black-depth (node kp ⟪ Red , proj2 vp ⟫  n1 (RBI.tree r)) ≡⟨ black-depth-cong _ (cong (λ k → node kp k n1 (RBI.tree r)) rb13) ⟩
-                black-depth (node kp vp n1 (RBI.tree r)) ≡⟨ black-depth-cong _ (sym x) ⟩
+                black-depth (RBI.tree r) ≡⟨ sym (proj2 (red-children-eq1 x pcolor rb09) ) ⟩
                 black-depth (PG.parent pg) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02 ) ⟩
                 black-depth (PG.uncle pg) ∎ where open ≡-Reasoning
             rb27 : black-depth n1 ≡ black-depth rp-left
             rb27 = begin
                black-depth n1 ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09) ⟩
-               black-depth (RBI.tree r) ≡⟨ ? ⟩
-               black-depth (RBI.repl r) ≡⟨ cong black-depth (sym eq) ⟩
-               black-depth (node rkey vr rp-left rp-right) ≡⟨ black-depth-cong _ (cong (λ k → node rkey k rp-left rp-right) rb23) ⟩
-               black-depth (node rkey ⟪ Red , proj2 vr ⟫ rp-left rp-right) ≡⟨ ? ⟩
-               black-depth rp-left ∎ 
+               black-depth (RBI.tree r) ≡⟨ RB-repl→eq _ _ (RBI.treerb r) rot ⟩
+               black-depth (RBI.repl r) ≡⟨ proj1 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
+               black-depth rp-left ∎
                   where open ≡-Reasoning
             rb19 : black-depth (node kp vp n1 rp-left) ≡ black-depth rp-right ⊔ black-depth (PG.uncle pg)
             rb19 = begin
-                black-depth (node kp vp n1 rp-left) ≡⟨ ? ⟩
-                black-depth (node kp ⟪ Red , proj2 vp ⟫ n1 rp-left) ≡⟨ ? ⟩
-                black-depth n1 ⊔ black-depth rp-left ≡⟨ ? ⟩
-                black-depth rp-left  ⊔ black-depth rp-left ≡⟨ ? ⟩
-                black-depth rp-left ≡⟨ ? ⟩
-                black-depth rp-right ≡⟨ ? ⟩
-                black-depth rp-right ⊔ black-depth rp-right ≡⟨ ? ⟩
+                black-depth (node kp vp n1 rp-left) ≡⟨ black-depth-resp A (node kp vp n1 rp-left) (node kp vp rp-left rp-left)  refl refl refl rb27 refl ⟩
+                black-depth (node kp vp rp-left rp-left) ≡⟨ black-depth-resp A (node kp vp rp-left rp-left) (node rkey vr rp-left rp-right)
+                     refl refl (trans (sym (cong proj1 rb13)) (sym (cong proj1 rb23))) refl (RBtreeEQ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))) ⟩
+                black-depth (node rkey vr rp-left rp-right) ≡⟨ black-depth-cong A eq ⟩
+                black-depth (RBI.repl r) ≡⟨ proj2 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
+                black-depth rp-right ≡⟨ sym ( ⊔-idem _ ) ⟩
+                black-depth rp-right ⊔ black-depth rp-right ≡⟨ cong (λ k → black-depth rp-right ⊔ k) rb18 ⟩
                 black-depth rp-right ⊔ black-depth (PG.uncle pg) ∎
                   where open ≡-Reasoning
             rb29 : color n1 ≡ Black
             rb29 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (sym (cong proj1 rb13)) )
             rb30 : color rp-left ≡ Black
             rb30 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)) (cong proj1 rb23))
+            rb32 : suc (black-depth (PG.uncle pg)) ≡ black-depth (PG.grand pg)
+            rb32 = sym (proj2 ( black-children-eq1 x₁ rb33 rb02 ))
             rb10 : RBtreeInvariant (node rkey ⟪ Black , proj2 vr ⟫ (node kp vp n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)))
             rb10 = rb-black _ _ rb19 (rbi-from-red-black _ _ kp vp rb06 rb26 rb27 rb29 rb30 rb13) (rb-red _ _ rb20 uncle-black rb18 rb28 rb05)
             rb17 : suc (black-depth (node kp vp n1 rp-left) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡ black-depth (PG.grand pg)
             rb17 = begin
-                 suc (black-depth (node kp vp n1 rp-left) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡⟨ ? ⟩
-                 suc ((black-depth rp-right ⊔ black-depth (PG.uncle pg)) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡⟨ ? ⟩
-                 suc (black-depth rp-right ⊔ black-depth (PG.uncle pg))  ≡⟨ ? ⟩
-                 suc (black-depth (PG.uncle pg) ⊔ black-depth (PG.uncle pg)) ≡⟨ ? ⟩
-                 suc (black-depth (PG.uncle pg))  ≡⟨ ? ⟩
+                 suc (black-depth (node kp vp n1 rp-left) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡⟨ cong (λ k → suc (k ⊔ _)) rb19 ⟩
+                 suc ((black-depth rp-right ⊔ black-depth (PG.uncle pg)) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡⟨ cong suc ( ⊔-idem _) ⟩
+                 suc (black-depth rp-right ⊔ black-depth (PG.uncle pg))  ≡⟨ cong (λ k → suc (k ⊔ _)) rb18 ⟩
+                 suc (black-depth (PG.uncle pg) ⊔ black-depth (PG.uncle pg)) ≡⟨ cong suc (⊔-idem _) ⟩
+                 suc (black-depth (PG.uncle pg))  ≡⟨ rb32 ⟩
                  black-depth (PG.grand pg) ∎
                  where open ≡-Reasoning
-        ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = ?
-        ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = ?
+        ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase52 where
+          insertCase52 : t
+          insertCase52 = next (PG.grand pg ∷ PG.rest pg) record {
+            tree = PG.grand pg
+            ; repl = rb01
+            ; origti = RBI.origti r
+            ; origrb = RBI.origrb r
+            ; treerb = rb02
+            ; replrb = rb10
+            ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
+            ; state = rebuild rb33 rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
+           } rb15 where
+                -- inner case, repl  is decomposed
+                -- lt          : key < kp
+                -- x           : PG.parent pg ≡ node kp vp (RBI.tree r) n1
+                -- x₁          : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
+                -- eq          : node rkey vr rp-left rp-right ≡ RBI.repl r
+            rb01 : bt (Color ∧ A)
+            rb01 = to-black (node rkey vr (to-red (node kg vg (PG.uncle pg) rp-left )) (node kp vp rp-right n1))
+            rb04 : key < kp
+            rb04 = lt
+            rb21 : kg < key   -- this can be a part of ParentGand relation
+            rb21 = si-property-> (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r)
+                 (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))))
+                 (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
+            rb16 : color n1 ≡ Black
+            rb16 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
+            rb13 : ⟪ Red , proj2 vp ⟫ ≡ vp
+            rb13 with subst (λ k → color k ≡ Red ) x pcolor
+            ... | refl = refl
+            rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
+            rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case2 pcolor)
+            ... | refl = refl
+            rb33 : color (PG.grand pg) ≡ Black
+            rb33 = subst (λ k → color k ≡ Black ) (sym x₁) (sym (cong proj1 rb14))
+            rb23 :  vr ≡ ⟪ Red , proj2 vr ⟫
+            rb23 with subst (λ k → color k ≡ Red ) (sym eq) repl-red
+            ... | refl = refl
+            rb20 : color rp-right ≡ Black
+            rb20 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r) ) (cong proj1 rb23))
+            rb03 : replacedRBTree key value (node kg _ (PG.uncle pg) (node kp _ (RBI.tree r) n1 ))
+               (node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left ) (node kp ⟪ Red , proj2 vp ⟫  rp-right n1 ))
+            rb03 = rbr-rotate-rl rp-left rp-right kg kp rkey rb20 rb21 rb04
+                (subst (λ k → replacedRBTree key value (RBI.tree r) k) (trans (sym eq) (cong (λ k → node rkey k rp-left rp-right) rb23 )) rot )
+            rb24 : node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) ≡ PG.grand pg
+            rb24 = begin
+               node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1)
+                   ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k (RBI.tree r) n1) ) rb14 rb13 ⟩
+               node kg vg (PG.uncle pg) (node kp vp (RBI.tree r) n1) ≡⟨ cong (λ k → node kg vg (PG.uncle pg) k ) (sym x) ⟩
+               node kg vg (PG.uncle pg) (PG.parent pg) ≡⟨ sym x₁ ⟩
+               PG.grand pg ∎ where open ≡-Reasoning
+            rb25 : node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp ⟪ Red , proj2 vp ⟫ rp-right n1) ≡ rb01
+            rb25 = begin
+                node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp ⟪ Red , proj2 vp ⟫ rp-right n1)
+                        ≡⟨ cong (λ k → node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp k rp-right n1)) rb13  ⟩
+                node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp vp rp-right n1)  ≡⟨ refl ⟩
+                rb01 ∎ where open ≡-Reasoning
+            rb11 : replacedRBTree key value (PG.grand pg) rb01
+            rb11 = subst₂ (λ j k → replacedRBTree key value j k) rb24 rb25 rb03
+            rb05 : RBtreeInvariant (PG.uncle pg)
+            rb05 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02)
+            rb06 : RBtreeInvariant n1
+            rb06 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x rb09)
+            rb26 : RBtreeInvariant rp-left
+            rb26 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
+            rb28 : RBtreeInvariant rp-right
+            rb28 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
+            rb31 : RBtreeInvariant (node rkey vr rp-left rp-right )
+            rb31 = subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)
+            rb18 : black-depth (PG.uncle pg) ≡ black-depth rp-left
+            rb18 = sym ( begin
+                black-depth rp-left ≡⟨ sym ( proj1 (red-children-eq1 (sym eq) repl-red (RBI.replrb r) )) ⟩
+                black-depth (RBI.repl r) ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+                black-depth (RBI.tree r) ≡⟨ sym (proj1 (red-children-eq1 x pcolor rb09) ) ⟩
+                black-depth (PG.parent pg) ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02 )) ⟩
+                black-depth (PG.uncle pg) ∎ ) where open ≡-Reasoning
+            rb27 : black-depth rp-right ≡ black-depth n1
+            rb27 = sym ( begin
+               black-depth n1 ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09)) ⟩
+               black-depth (RBI.tree r) ≡⟨ RB-repl→eq _ _ (RBI.treerb r) rot ⟩
+               black-depth (RBI.repl r) ≡⟨ proj2 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
+               black-depth rp-right ∎ )
+                  where open ≡-Reasoning
+            rb19 : black-depth (PG.uncle pg) ⊔ black-depth rp-left ≡ black-depth (node kp vp rp-right n1)
+            rb19 = sym ( begin
+                black-depth (node kp vp rp-right n1)  ≡⟨ black-depth-resp A (node kp vp rp-right n1) (node kp vp rp-right rp-right)  refl refl refl refl (sym rb27) ⟩
+                black-depth (node kp vp rp-right rp-right) ≡⟨ black-depth-resp A (node kp vp rp-right rp-right) (node rkey vr rp-left rp-right)
+                     refl refl (trans (sym (cong proj1 rb13)) (sym (cong proj1 rb23))) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)))) refl ⟩
+                black-depth (node rkey vr rp-left rp-right) ≡⟨ black-depth-cong A eq ⟩
+                black-depth (RBI.repl r) ≡⟨ proj1 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
+                black-depth rp-left ≡⟨ sym ( ⊔-idem _ ) ⟩
+                black-depth  rp-left ⊔ black-depth rp-left ≡⟨ cong (λ k → k ⊔ black-depth rp-left ) (sym rb18) ⟩
+                black-depth (PG.uncle pg) ⊔ black-depth rp-left ∎ )
+                  where open ≡-Reasoning
+            rb29 : color n1 ≡ Black
+            rb29 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (sym (cong proj1 rb13)) )
+            rb30 : color rp-left ≡ Black
+            rb30 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)) (cong proj1 rb23))
+            rb32 : suc (black-depth (PG.uncle pg)) ≡ black-depth (PG.grand pg)
+            rb32 = sym (proj1 ( black-children-eq1 x₁ rb33 rb02 ))
+            rb10 : RBtreeInvariant (node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left ) (node kp vp rp-right n1) )
+            rb10 = rb-black _ _ rb19 (rb-red _ _ uncle-black rb30 rb18 rb05 rb26 ) (rbi-from-red-black _ _ _ _ rb28 rb06 rb27 rb20 rb16 rb13 )
+            rb17 : suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ⊔ black-depth (node kp vp rp-right n1)) ≡ black-depth (PG.grand pg)
+            rb17 = begin
+                 suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ⊔ black-depth (node kp vp rp-right n1)) ≡⟨ cong (λ k → suc (_ ⊔ k)) (sym rb19) ⟩
+                 suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ⊔ (black-depth (PG.uncle pg) ⊔ black-depth rp-left)) ≡⟨ cong suc ( ⊔-idem _) ⟩
+                 suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ) ≡⟨ cong (λ k → suc (_ ⊔ k)) (sym rb18) ⟩
+                 suc (black-depth (PG.uncle pg) ⊔ black-depth (PG.uncle pg)) ≡⟨ cong suc (⊔-idem _) ⟩
+                 suc (black-depth (PG.uncle pg))  ≡⟨ rb32 ⟩
+                 black-depth (PG.grand pg) ∎
+                    where open ≡-Reasoning
+        ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase52 where
+          insertCase52 : t
+          insertCase52 = next (PG.grand pg ∷ PG.rest pg) record {
+            tree = PG.grand pg
+            ; repl = rb01
+            ; origti = RBI.origti r
+            ; origrb = RBI.origrb r
+            ; treerb = rb02
+            ; replrb = subst (λ k → RBtreeInvariant k) rb10 (rb-black _ _ rb18 (rb-red _ _ uncle-black rb16 rb19 rb05 rb06) (RBI.replrb r) )
+            ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
+            ; state = rebuild rb33 rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
+           } rb15 where
+                -- outer case, repl  is not decomposed
+                -- lt          : kp < key
+                -- x           : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
+                -- x₁          : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
+            rb01 : bt (Color ∧ A)
+            rb01 = to-black (node kp vp  (to-red (node kg vg (PG.uncle pg) n1) )(node rkey vr rp-left rp-right))
+            rb04 : kp < key
+            rb04 = lt
+            rb16 : color n1 ≡ Black
+            rb16 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
+            rb13 : ⟪ Red , proj2 vp ⟫ ≡ vp
+            rb13 with subst (λ k → color k ≡ Red ) x pcolor
+            ... | refl = refl
+            rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
+            rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case2 pcolor)
+            ... | refl = refl
+            rb33 : color (PG.grand pg) ≡ Black
+            rb33 = subst (λ k → color k ≡ Black ) (sym x₁) (sym (cong proj1 rb14))
+            rb03 : replacedRBTree key value (node kg _ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ))
+                (node kp ⟪ Black , proj2 vp ⟫  (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) n1 ) repl )
+            rb03 = rbr-rotate-rr repl-red rb04 rot
+            rb10 : node kp ⟪ Black , proj2 vp ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) n1 ) repl ≡ rb01
+            rb10 = cong (λ  k → node _ _  _ k ) (sym eq)
+            rb12 : node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r)) ≡ PG.grand pg
+            rb12 = begin
+                 node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r))
+                       ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k n1 (RBI.tree r) ) ) rb14 rb13 ⟩
+                 node kg vg (PG.uncle pg) _ ≡⟨ cong (λ k → node _ _ _ k) (sym x) ⟩
+                 node kg vg (PG.uncle pg) (PG.parent pg) ≡⟨ sym x₁ ⟩
+                 PG.grand pg ∎ where open ≡-Reasoning
+            rb11 : replacedRBTree key value (PG.grand pg) rb01
+            rb11 = subst₂ (λ j k → replacedRBTree key value j k) rb12 rb10 rb03
+            rb05 : RBtreeInvariant (PG.uncle pg)
+            rb05 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02)
+            rb06 : RBtreeInvariant n1
+            rb06 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb09)
+            rb19 : black-depth (PG.uncle pg) ≡ black-depth n1
+            rb19 = sym (trans (sym ( proj1 (red-children-eq x (sym (cong proj1 rb13))  rb09) )) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02))))
+            rb18 : black-depth (PG.uncle pg) ⊔ black-depth n1 ≡ black-depth repl
+            rb18 = sym ( begin
+               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+               black-depth (RBI.tree r) ≡⟨ sym ( RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09)) ⟩
+               black-depth n1 ≡⟨ sym (⊔-idem (black-depth n1)) ⟩
+               black-depth n1 ⊔ black-depth n1 ≡⟨ cong (λ k → k ⊔ _) (sym rb19) ⟩
+               black-depth (PG.uncle pg) ⊔ black-depth n1 ∎ ) where open ≡-Reasoning
+                -- suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg))) ≡ black-depth (PG.grand pg)
+            rb17 : suc (black-depth (PG.uncle pg) ⊔ black-depth n1 ⊔ black-depth (node rkey vr rp-left rp-right)) ≡ black-depth (PG.grand pg)
+            rb17 = begin
+                suc (black-depth (PG.uncle pg) ⊔ black-depth n1 ⊔ black-depth (node rkey vr rp-left rp-right))
+                      ≡⟨ cong₂ (λ j k → suc (j ⊔ black-depth k)) rb18 eq  ⟩
+                suc (black-depth repl ⊔ black-depth repl) ≡⟨ ⊔-idem _ ⟩
+                suc (black-depth repl ) ≡⟨ cong suc (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
+                suc (black-depth (RBI.tree r) ) ≡⟨ cong suc (sym (proj2 (red-children-eq x (cong proj1 (sym rb13)) rb09))) ⟩
+                suc (black-depth (PG.parent pg) ) ≡⟨ sym (proj2 (black-children-eq refl (cong proj1 (sym rb14)) (subst (λ k → RBtreeInvariant k) x₁ rb02))) ⟩
+                black-depth (node kg vg (PG.uncle pg) (PG.parent pg)) ≡⟨ cong black-depth (sym x₁) ⟩
+                black-depth (PG.grand pg) ∎ where open ≡-Reasoning
     replaceRBP1 : t
     replaceRBP1 with RBI.state r
     ... | rebuild ceq bdepth-eq ¬leaf rot = rebuildCase ceq bdepth-eq ¬leaf rot
@@ -2404,9 +2623,118 @@
             rb06 : RBtreeInvariant rb01
             rb06 = subst (λ k → RBtreeInvariant (node kp k repl n1))  rb04
                ( rb-black _ _ rb07 (RBI.replrb r) (RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))))
-       insertCase1 | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = ?
-       insertCase1 | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = ?
-       insertCase1 | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = ?
+       ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
+            tree = PG.parent pg
+            ; repl = rb01
+            ; origti = RBI.origti r
+            ; origrb = RBI.origrb r
+            ; treerb = treerb pg
+            ; replrb = rb06
+            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
+            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
+                (subst (λ k → replacedRBTree key value k (node kp vp n1 repl) ) (sym x) (rb02 rb04 ))
+           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
+               --- x  : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
+               --- x₁ : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
+            rb01 : bt (Color ∧ A)
+            rb01 = node kp vp n1 repl
+            rb03 : kp < key
+            rb03 = lt
+            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
+            rb04 with subst (λ k → color k ≡ Black) x pcolor
+            ... | refl = refl
+            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp n1 (RBI.tree r) ) (node kp vp n1 repl )
+            rb02 eq = subst (λ k → replacedRBTree key value (node kp k n1 (RBI.tree r) ) (node kp k n1 repl )) eq (rbr-black-right repl-red rb03 rot )
+            rb07 : black-depth repl ≡ black-depth n1
+            rb07 = begin
+               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+               black-depth (RBI.tree r) ≡⟨ sym ( RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg))) ⟩
+               black-depth n1 ∎
+                 where open ≡-Reasoning
+            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
+            rb05 refl = begin
+               suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong suc (cong (λ k → black-depth n1 ⊔ k ) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
+               suc (black-depth n1 ⊔ black-depth (RBI.tree r)) ≡⟨ refl ⟩
+               black-depth (node kp vp n1 (RBI.tree r) ) ≡⟨ cong black-depth (sym x) ⟩
+               black-depth (PG.parent pg) ∎
+                 where open ≡-Reasoning
+            rb06 : RBtreeInvariant rb01
+            rb06 = subst (λ k → RBtreeInvariant (node kp k n1 repl ))  rb04
+               ( rb-black _ _ (sym rb07) (RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))) (RBI.replrb r) )
+       insertCase1 | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
+            tree = PG.parent pg
+            ; repl = rb01
+            ; origti = RBI.origti r
+            ; origrb = RBI.origrb r
+            ; treerb = treerb pg
+            ; replrb = rb06
+            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
+            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
+                (subst (λ k → replacedRBTree key value k (node kp vp repl n1) ) (sym x) (rb02 rb04 ))
+           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
+            rb01 : bt (Color ∧ A)
+            rb01 = node kp vp repl n1
+            rb03 : key < kp
+            rb03 = lt
+            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
+            rb04 with subst (λ k → color k ≡ Black) x pcolor
+            ... | refl = refl
+            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp (RBI.tree r) n1) (node kp vp repl n1)
+            rb02 eq = subst (λ k → replacedRBTree key value (node kp k (RBI.tree r) n1) (node kp k repl n1)) eq (rbr-black-left repl-red rb03 rot )
+            rb07 : black-depth repl ≡ black-depth n1
+            rb07 = begin
+               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+               black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)) ⟩
+               black-depth n1 ∎
+                 where open ≡-Reasoning
+            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
+            rb05 refl = begin
+               suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong suc (cong (λ k → k ⊔ black-depth n1) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
+               suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ refl ⟩
+               black-depth (node kp vp (RBI.tree r) n1) ≡⟨ cong black-depth (sym x) ⟩
+               black-depth (PG.parent pg) ∎
+                 where open ≡-Reasoning
+            rb06 : RBtreeInvariant rb01
+            rb06 = subst (λ k → RBtreeInvariant (node kp k repl n1))  rb04
+               ( rb-black _ _ rb07 (RBI.replrb r) (RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))))
+       insertCase1 | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
+            tree = PG.parent pg
+            ; repl = rb01
+            ; origti = RBI.origti r
+            ; origrb = RBI.origrb r
+            ; treerb = treerb pg
+            ; replrb = rb06
+            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
+            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
+                (subst (λ k → replacedRBTree key value k (node kp vp n1 repl) ) (sym x) (rb02 rb04 ))
+           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
+                -- x   : PG.parent pg ≡ node kp vp (RBI.tree r) n1
+                -- x₁  : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
+            rb01 : bt (Color ∧ A)
+            rb01 = node kp vp n1 repl
+            rb03 : kp < key
+            rb03 = lt
+            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
+            rb04 with subst (λ k → color k ≡ Black) x pcolor
+            ... | refl = refl
+            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp n1 (RBI.tree r) ) (node kp vp n1 repl )
+            rb02 eq = subst (λ k → replacedRBTree key value (node kp k n1 (RBI.tree r) ) (node kp k n1 repl )) eq (rbr-black-right repl-red rb03 rot )
+            rb07 : black-depth repl ≡ black-depth n1
+            rb07 = begin
+               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+               black-depth (RBI.tree r) ≡⟨ sym ( RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg))) ⟩
+               black-depth n1 ∎
+                 where open ≡-Reasoning
+            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
+            rb05 refl = begin
+               suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong suc (cong (λ k → black-depth n1 ⊔ k ) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
+               suc (black-depth n1 ⊔ black-depth (RBI.tree r)) ≡⟨ refl ⟩
+               black-depth (node kp vp n1 (RBI.tree r) ) ≡⟨ cong black-depth (sym x) ⟩
+               black-depth (PG.parent pg) ∎
+                 where open ≡-Reasoning
+            rb06 : RBtreeInvariant rb01
+            rb06 = subst (λ k → RBtreeInvariant (node kp k n1 repl ))  rb04
+               ( rb-black _ _ (sym rb07) (RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))) (RBI.replrb r) )
     ... | Red with PG.uncle pg in uneq
     ... | leaf = insertCase5 repl refl pg rot repl-red (cong color uneq) pcolor
     ... | node key₁ ⟪ Black , value₁ ⟫ t₁ t₂ = insertCase5 repl refl pg rot repl-red (cong color uneq) pcolor
@@ -2471,12 +2799,160 @@
                   suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
                   black-depth (to-black (PG.uncle pg)) ∎
                      where open ≡-Reasoning
+               rb15 : suc (length (PG.rest pg)) < length stack
+               rb15 = begin
+                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
+                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
+                  length stack ∎
+                     where open ≤-Reasoning
+    ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
+        insertCase2 : t
+        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
+            record {
+                 tree = PG.grand pg
+                 ; repl = to-red (node kg vg (to-black (node kp vp n1 repl)) (to-black (PG.uncle pg))  )
+                 ; origti = RBI.origti r
+                 ; origrb = RBI.origrb r
+                 ; treerb = rb01
+                 ; replrb = rb-red _ _ refl (RBtreeToBlackColor _ rb02) rb12 (rb-black _ _ (sym rb13) rb04 (RBI.replrb r)) (RBtreeToBlack _ rb02)
+                  ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
+                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) rb09 refl (rbr-flip-lr repl-red (rb05 refl uneq) rb06 rb21 rot))
+             }  rb15 where
+               --
+               -- lt       : kp < key
+               --  x       : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
+               --- x₁      : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
+               --
+               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
+               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
+               rb01 : RBtreeInvariant (PG.grand pg)
+               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
+               rb02 : RBtreeInvariant (PG.uncle pg)
+               rb02 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
+               rb03 : RBtreeInvariant (PG.parent pg)
+               rb03 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
+               rb04 : RBtreeInvariant n1
+               rb04 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
+               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
+               rb05 refl refl = refl
+               rb08 : treeInvariant (PG.parent pg)
+               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
+               rb07 : treeInvariant (node kp vp n1 (RBI.tree r) )
+               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
+               rb06 : kp < key
+               rb06 = lt
+               rb21 : key < kg   -- this can be a part of ParentGand relation
+               rb21 = si-property-< (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r)
+                     (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))))
+                     (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
+               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
+               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case1 pcolor)
+               ... | refl = refl
+               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
+               rb11 with subst (λ k → color k ≡ Red) x pcolor
+               ... | refl = refl
+               rb09 : node kg ⟪ Black , proj2 vg ⟫  (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ) (PG.uncle pg) ≡ PG.grand pg
+               rb09 = sym ( begin
+                   PG.grand pg ≡⟨ x₁ ⟩
+                   node kg vg  (PG.parent pg) (PG.uncle pg) ≡⟨ cong (λ k → node kg vg k (PG.uncle pg)) x ⟩
+                   node kg vg  (node kp vp n1 (RBI.tree r) ) (PG.uncle pg)  ≡⟨ cong₂ (λ j k → node kg j  (node kp k n1 (RBI.tree r) ) (PG.uncle pg) ) rb10 rb11  ⟩
+                   node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ) (PG.uncle pg) ∎ )
+                     where open ≡-Reasoning
+               rb13 : black-depth repl ≡ black-depth n1
+               rb13 = begin
+                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+                  black-depth (RBI.tree r) ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
+                  black-depth n1 ∎
+                     where open ≡-Reasoning
+               rb12 : suc (black-depth n1 ⊔ black-depth repl) ≡ black-depth (to-black (PG.uncle pg))
+               rb12 = begin
+                  suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong (λ k → suc (black-depth n1 ⊔ k)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
+                  suc (black-depth n1 ⊔ black-depth (RBI.tree r)) ≡⟨ cong (λ k → suc (black-depth n1 ⊔ k)) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03))) ⟩
+                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
+                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj1 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
+                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01)) ⟩
+                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
+                  black-depth (to-black (PG.uncle pg)) ∎
+                     where open ≡-Reasoning
+               rb15 : suc (length (PG.rest pg)) < length stack
+               rb15 = begin
+                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
+                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
+                  length stack ∎
+                     where open ≤-Reasoning
+    ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
+        insertCase2 : t
+        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
+            record {
+                 tree = PG.grand pg
+                 ; repl = to-red (node kg vg (to-black (PG.uncle pg)) (to-black (node kp vp repl n1)) )
+                 ; origti = RBI.origti r
+                 ; origrb = RBI.origrb r
+                 ; treerb = rb01
+                 ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
+                 ; replrb = rb-red _ _ (RBtreeToBlackColor _ rb02) refl rb12 (RBtreeToBlack _ rb02) (rb-black _ _ rb13 (RBI.replrb r) rb04)
+                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) rb09 refl  (rbr-flip-rl repl-red (rb05 refl uneq) rb21 rb06 rot))
+             }  rb15 where
+                 -- x   : PG.parent pg ≡ node kp vp (RBI.tree r) n1
+                 -- x₁  : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
+               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
+               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
+               rb01 :  RBtreeInvariant (PG.grand pg)
+               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
+               rb02 : RBtreeInvariant (PG.uncle pg)
+               rb02 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
+               rb03 : RBtreeInvariant (PG.parent pg)
+               rb03 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
+               rb04 : RBtreeInvariant n1
+               rb04 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
+               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
+               rb05 refl refl = refl
+               rb08 : treeInvariant (PG.parent pg)
+               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
+               rb07 : treeInvariant (node kp vp (RBI.tree r) n1)
+               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
+               rb06 : key < kp
+               rb06 = lt
+               rb21 : kg < key   -- this can be a part of ParentGand relation
+               rb21 = si-property-> (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r)
+                     (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))))
+                     (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
+               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
+               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case2 pcolor)
+               ... | refl = refl
+               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
+               rb11 with subst (λ k → color k ≡ Red) x pcolor
+               ... | refl = refl
+               rb09 : node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) ≡ PG.grand pg
+               rb09 = sym ( begin
+                   PG.grand pg ≡⟨ x₁ ⟩
+                   node kg vg (PG.uncle pg) (PG.parent pg)  ≡⟨ cong (λ k → node kg vg (PG.uncle pg) k) x ⟩
+                   node kg vg (PG.uncle pg) (node kp vp (RBI.tree r) n1)  ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k (RBI.tree r) n1) ) rb10 rb11  ⟩
+                   node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) ∎ )
+                     where open ≡-Reasoning
+               rb13 : black-depth repl ≡ black-depth n1
+               rb13 = begin
+                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+                  black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03) ⟩
+                  black-depth n1 ∎
+                     where open ≡-Reasoning
+               -- rb12 : suc (black-depth repl ⊔ black-depth n1) ≡ black-depth (to-black (PG.uncle pg))
+               rb12 : black-depth (to-black (PG.uncle pg)) ≡ suc (black-depth repl ⊔ black-depth n1)
+               rb12 = sym ( begin
+                  suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
+                  suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
+                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
+                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj2 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
+                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01))) ⟩
+                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
+                  black-depth (to-black (PG.uncle pg)) ∎ )
+                     where open ≡-Reasoning
                rb17 : suc (black-depth repl ⊔ black-depth n1) ⊔ black-depth (to-black (PG.uncle pg)) ≡ black-depth (PG.grand pg)
                rb17 = begin
-                  suc (black-depth repl ⊔ black-depth n1) ⊔ black-depth (to-black (PG.uncle pg)) ≡⟨ cong (λ k → k ⊔ black-depth (to-black (PG.uncle pg))) rb12 ⟩
+                  suc (black-depth repl ⊔ black-depth n1) ⊔ black-depth (to-black (PG.uncle pg)) ≡⟨ cong (λ k → k ⊔ black-depth (to-black (PG.uncle pg))) (sym rb12) ⟩
                   black-depth (to-black (PG.uncle pg)) ⊔ black-depth (to-black (PG.uncle pg)) ≡⟨ ⊔-idem _ ⟩
                   black-depth (to-black (PG.uncle pg)) ≡⟨ sym (to-black-eq (PG.uncle pg) (cong color uneq )) ⟩
-                  suc (black-depth (PG.uncle pg)) ≡⟨ sym ( proj2 (black-children-eq x₁ (cong proj1 rb10) rb01 )) ⟩
+                  suc (black-depth (PG.uncle pg)) ≡⟨ sym ( proj1 (black-children-eq x₁ (cong proj1 rb10) rb01 )) ⟩
                   black-depth (PG.grand pg) ∎
                      where open ≡-Reasoning
                rb15 : suc (length (PG.rest pg)) < length stack
@@ -2485,7 +2961,86 @@
                   length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
                   length stack ∎
                      where open ≤-Reasoning
-    ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = {!!}
-    ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = {!!}
-    ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = {!!}
+    ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
+           --- lt : kp < key
+           --- x  : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
+           --- x₁ : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
+        insertCase2 : t
+        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
+            record {
+                 tree = PG.grand pg
+                 ; repl = to-red (node kg vg (to-black (PG.uncle pg)) (to-black (node kp vp n1 repl )) )
+                 ; origti = RBI.origti r
+                 ; origrb = RBI.origrb r
+                 ; treerb = rb01
+                 ; replrb = rb-red _ _ (RBtreeToBlackColor _ rb02) refl rb12  (RBtreeToBlack _ rb02) (rb-black _ _ (sym rb13) rb04 (RBI.replrb r) )
+                 ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
+                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) (sym rb09) refl  (rbr-flip-rr repl-red (rb05 refl uneq) rb06 rot))
+             }  rb15 where
+               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
+               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
+               rb01 :  RBtreeInvariant (PG.grand pg)
+               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
+               rb02 : RBtreeInvariant (PG.uncle pg)
+               rb02 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
+               rb03 : RBtreeInvariant (PG.parent pg)
+               rb03 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
+               rb04 : RBtreeInvariant n1
+               rb04 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
+               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
+               rb05 refl refl = refl
+               rb08 : treeInvariant (PG.parent pg)
+               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
+               rb07 : treeInvariant (node kp vp n1 (RBI.tree r) )
+               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
+               rb06 : kp < key
+               rb06 = lt
+               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
+               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case2 pcolor)
+               ... | refl = refl
+               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
+               rb11 with subst (λ k → color k ≡ Red) x pcolor
+               ... | refl = refl
+               rb09 : PG.grand pg ≡ node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) )
+               rb09 = begin
+                   PG.grand pg ≡⟨ x₁ ⟩
+                   node kg vg (PG.uncle pg) (PG.parent pg) ≡⟨ cong (λ k → node kg vg (PG.uncle pg) k) x ⟩
+                   node kg vg (PG.uncle pg) (node kp vp n1 (RBI.tree r) )  ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k n1 (RBI.tree r) ) ) rb10 rb11  ⟩
+                   node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) )  ∎
+                     where open ≡-Reasoning
+               rb13 : black-depth repl ≡ black-depth n1
+               rb13 = begin
+                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
+                  black-depth (RBI.tree r) ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
+                  black-depth n1 ∎
+                     where open ≡-Reasoning
+               rb12 : black-depth (to-black (PG.uncle pg)) ≡ suc (black-depth n1 ⊔ black-depth repl)
+               rb12 = sym ( begin
+                  suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong suc (⊔-comm (black-depth n1) _) ⟩
+                  suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
+                  suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03))) ⟩
+                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
+                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj1 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
+                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01))) ⟩
+                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
+                  black-depth (to-black (PG.uncle pg)) ∎ )
+                     where open ≡-Reasoning
+               rb15 : suc (length (PG.rest pg)) < length stack
+               rb15 = begin
+                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
+                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
+                  length stack ∎
+                     where open ≤-Reasoning
 
+
+insertRBTreeP : {n m : Level} {A : Set n} {t : Set m} → (tree : bt (Color ∧ A)) → (key : ℕ) → (value : A)
+   → treeInvariant tree → RBtreeInvariant tree
+   → (exit : (stack  : List (bt (Color ∧ A))) → stack ≡ (tree ∷ []) → RBI key value tree stack → t ) → t
+insertRBTreeP {n} {m} {A} {t} orig key value ti rbi exit = TerminatingLoopS (bt (Color ∧ A) ∧ List (bt (Color ∧ A)))
+ {λ p → RBtreeInvariant (proj1 p) ∧ stackInvariant key (proj1 p) orig (proj2 p) } (λ p → bt-depth (proj1 p)) ⟪ orig , orig ∷ [] ⟫ ⟪ rbi , s-nil ⟫
+       $ λ p RBP findLoop → findRBT key (proj1 p) orig (proj2 p) RBP  (λ t1 s1 P2 lt1 → findLoop ⟪ t1 ,  s1  ⟫ P2 lt1 )
+       $ λ tr1 st P2 O → createRBT key value orig rbi ti tr1 st (proj2 P2) O
+       $ λ st rbi → TerminatingLoopS (List (bt (Color ∧ A))) {λ stack → RBI key value orig stack }
+          (λ stack  → length stack ) st rbi
+            $ λ stack rbi replaceLoop → replaceRBP key value orig stack rbi (λ stack1 rbi1 lt → replaceLoop stack1 rbi1 lt )
+            $ λ stack eq r → exit stack eq r
--- a/hoareBinaryTree2.agda	Mon Jun 17 08:24:11 2024 +0900
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,2354 +0,0 @@
-module hoareBinaryTree2 where
-
-open import Level hiding (suc ; zero ; _⊔_ )
-
-open import Data.Nat hiding (compare)
-open import Data.Nat.Properties as NatProp
-open import Data.Maybe
--- open import Data.Maybe.Properties
-open import Data.Empty
-open import Data.List
-open import Data.Product
-
-open import Function as F hiding (const)
-
-open import Relation.Binary
-open import Relation.Binary.PropositionalEquality
-open import Relation.Nullary
-open import logic
-
-
---
---
---  no children , having left node , having right node , having both
---
-data bt {n : Level} (A : Set n) : Set n where
-  leaf : bt A
-  node :  (key : ℕ) → (value : A) →
-    (left : bt A ) → (right : bt A ) → bt A
-
-node-key : {n : Level} {A : Set n} → bt A → Maybe ℕ
-node-key (node key _ _ _) = just key
-node-key _ = nothing
-
-node-value : {n : Level} {A : Set n} → bt A → Maybe A
-node-value (node _ value _ _) = just value
-node-value _ = nothing
-
-bt-depth : {n : Level} {A : Set n} → (tree : bt A ) → ℕ
-bt-depth leaf = 0
-bt-depth (node key value t t₁) = suc (bt-depth t  ⊔ bt-depth t₁ )
-
-bt-ne : {n : Level} {A : Set n} {key : ℕ} {value : A} {t t₁ : bt A} → ¬ ( leaf ≡ node key value t t₁ )
-bt-ne {n} {A} {key} {value} {t} {t₁} () 
-
-open import Data.Unit hiding ( _≟_ ) -- ;  _≤?_ ; _≤_)
-
-tr< : {n : Level} {A : Set n} → (key : ℕ) → bt A → Set
-tr< {_} {A} key leaf = ⊤
-tr< {_} {A} key (node key₁ value tr tr₁) = (key₁ < key ) ∧ tr< key tr  ∧  tr< key tr₁
-
-tr> : {n : Level} {A : Set n} → (key : ℕ) → bt A → Set
-tr> {_} {A} key leaf = ⊤
-tr> {_} {A} key (node key₁ value tr tr₁) = (key < key₁ ) ∧ tr> key tr  ∧  tr> key tr₁
-
---
---
-data treeInvariant {n : Level} {A : Set n} : (tree : bt A) → Set n where
-    t-leaf : treeInvariant leaf
-    t-single : (key : ℕ) → (value : A) →  treeInvariant (node key value leaf leaf)
-    t-right : (key key₁ : ℕ) → {value value₁ : A} → {t₁ t₂ : bt A} → key < key₁
-       → tr> key t₁
-       → tr> key t₂
-       → treeInvariant (node key₁ value₁ t₁ t₂)
-       → treeInvariant (node key value leaf (node key₁ value₁ t₁ t₂))
-    t-left  : (key key₁ : ℕ) → {value value₁ : A} → {t₁ t₂ : bt A} → key < key₁
-       → tr< key₁ t₁
-       → tr< key₁ t₂
-       → treeInvariant (node key value t₁ t₂)
-       → treeInvariant (node key₁ value₁ (node key value t₁ t₂) leaf )
-    t-node  : (key key₁ key₂ : ℕ) → {value value₁ value₂ : A} → {t₁ t₂ t₃ t₄ : bt A} → key < key₁ → key₁ < key₂
-       → tr< key₁ t₁
-       → tr< key₁ t₂
-       → tr> key₁ t₃
-       → tr> key₁ t₄
-       → treeInvariant (node key value t₁ t₂)
-       → treeInvariant (node key₂ value₂ t₃ t₄)
-       → treeInvariant (node key₁ value₁ (node key value t₁ t₂) (node key₂ value₂ t₃ t₄))
-
---
---  stack always contains original top at end (path of the tree)
---
-data stackInvariant {n : Level} {A : Set n}  (key : ℕ) : (top orig : bt A) → (stack  : List (bt A)) → Set n where
-    s-nil :  {tree0 : bt A} → stackInvariant key tree0 tree0 (tree0 ∷ [])
-    s-right :  (tree tree0 tree₁ : bt A) → {key₁ : ℕ } → {v1 : A } → {st : List (bt A)}
-        → key₁ < key  →  stackInvariant key (node key₁ v1 tree₁ tree) tree0 st → stackInvariant key tree tree0 (tree ∷ st)
-    s-left :  (tree₁ tree0 tree : bt A) → {key₁ : ℕ } → {v1 : A } → {st : List (bt A)}
-        → key  < key₁ →  stackInvariant key (node key₁ v1 tree₁ tree) tree0 st → stackInvariant key tree₁ tree0 (tree₁ ∷ st)
-
-data replacedTree  {n : Level} {A : Set n} (key : ℕ) (value : A)  : (before after : bt A ) → Set n where
-    r-leaf : replacedTree key value leaf (node key value leaf leaf)
-    r-node : {value₁ : A} → {t t₁ : bt A} → replacedTree key value (node key value₁ t t₁) (node key value t t₁)
-    r-right : {k : ℕ } {v1 : A} → {t t1 t2 : bt A}
-          → k < key →  replacedTree key value t2 t →  replacedTree key value (node k v1 t1 t2) (node k v1 t1 t)
-    r-left : {k : ℕ } {v1 : A} → {t t1 t2 : bt A}
-          → key < k →  replacedTree key value t1 t →  replacedTree key value (node k v1 t1 t2) (node k v1 t t2)
-
-add< : { i : ℕ } (j : ℕ ) → i < suc i + j
-add<  {i} j = begin
-        suc i ≤⟨ m≤m+n (suc i) j ⟩
-        suc i + j ∎  where open ≤-Reasoning
-
-nat-≤> : { x y : ℕ } → x ≤ y → y < x → ⊥
-nat-≤>  (s≤s x<y) (s≤s y<x) = nat-≤> x<y y<x
-nat-<> : { x y : ℕ } → x < y → y < x → ⊥
-nat-<>  (s≤s x<y) (s≤s y<x) = nat-<> x<y y<x
-
-nat-<≡ : { x : ℕ } → x < x → ⊥
-nat-<≡  (s≤s lt) = nat-<≡ lt
-
-nat-≡< : { x y : ℕ } → x ≡ y → x < y → ⊥
-nat-≡< refl lt = nat-<≡ lt
-
-treeTest1  : bt ℕ
-treeTest1  =  node 0 0 leaf (node 3 1 (node 2 5 (node 1 7 leaf leaf ) leaf) (node 5 5 leaf leaf))
-treeTest2  : bt ℕ
-treeTest2  =  node 3 1 (node 2 5 (node 1 7 leaf leaf ) leaf) (node 5 5 leaf leaf)
-
-treeInvariantTest1  : treeInvariant treeTest1
-treeInvariantTest1  = t-right _ _ (m≤m+n _ 2)
-    ⟪ add< _ , ⟪ ⟪ add< _ , _ ⟫ , _ ⟫ ⟫
-    ⟪ add< _ , ⟪ _ , _ ⟫ ⟫ (t-node _ _ _ (add< 0) (add< 1) ⟪ add< _ , ⟪ _ , _ ⟫ ⟫  _ _ _ (t-left _ _ (add< 0) _ _ (t-single 1 7)) (t-single 5 5) )
-
-stack-top :  {n : Level} {A : Set n} (stack  : List (bt A)) → Maybe (bt A)
-stack-top [] = nothing
-stack-top (x ∷ s) = just x
-
-stack-last :  {n : Level} {A : Set n} (stack  : List (bt A)) → Maybe (bt A)
-stack-last [] = nothing
-stack-last (x ∷ []) = just x
-stack-last (x ∷ s) = stack-last s
-
-stackInvariantTest1 : stackInvariant 4 treeTest2 treeTest1 ( treeTest2 ∷ treeTest1 ∷ [] )
-stackInvariantTest1 = s-right _ _ _ (add< 3) (s-nil  )
-
-si-property0 :  {n : Level} {A : Set n} {key : ℕ} {tree tree0 : bt A} → {stack  : List (bt A)} →  stackInvariant key tree tree0 stack → ¬ ( stack ≡ [] )
-si-property0  (s-nil  ) ()
-si-property0  (s-right _ _ _ x si) ()
-si-property0  (s-left _ _ _ x si) ()
-
-si-property1 :  {n : Level} {A : Set n} {key : ℕ} {tree tree0 tree1 : bt A} → {stack  : List (bt A)} →  stackInvariant key tree tree0 (tree1 ∷ stack)
-   → tree1 ≡ tree
-si-property1 (s-nil   ) = refl
-si-property1 (s-right _ _ _ _  si) = refl
-si-property1 (s-left _ _ _ _  si) = refl
-
-si-property2 :  {n : Level} {A : Set n} {key : ℕ} {tree tree0 tree1 : bt A} → (stack  : List (bt A)) →  stackInvariant key tree tree0 (tree1 ∷ stack)
-   → ¬ ( just leaf ≡ stack-last stack )
-si-property2 (.leaf ∷ []) (s-right _ _ tree₁ x ()) refl
-si-property2 (x₁ ∷ x₂ ∷ stack) (s-right _ _ tree₁ x si) eq = si-property2 (x₂ ∷ stack) si eq
-si-property2 (.leaf ∷ []) (s-left _ _ tree₁ x ()) refl
-si-property2 (x₁ ∷ x₂ ∷ stack) (s-left _ _ tree₁ x si) eq = si-property2 (x₂ ∷ stack) si eq
-
-si-property-< :  {n : Level} {A : Set n} {key kp : ℕ} {value₂ : A} {tree orig tree₃ : bt A} → {stack  : List (bt A)}
-   → ¬ ( tree ≡ leaf )
-   → treeInvariant (node kp value₂ tree  tree₃ )
-   → stackInvariant key tree orig (tree ∷ node kp value₂ tree  tree₃ ∷ stack)
-   → key < kp
-si-property-< ne (t-node _ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (s-right .(node _ _ _ _) _ .(node _ _ _ _) x s-nil) = ⊥-elim (nat-<> x₁ x₂)
-si-property-< ne (t-node _ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (s-right .(node _ _ _ _) _ .(node _ _ _ _) x (s-right .(node _ _ (node _ _ _ _) (node _ _ _ _)) _ tree₁ x₇ si)) = ⊥-elim (nat-<> x₁ x₂)
-si-property-< ne (t-node _ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (s-right .(node _ _ _ _) _ .(node _ _ _ _) x (s-left .(node _ _ (node _ _ _ _) (node _ _ _ _)) _ tree x₇ si)) = ⊥-elim (nat-<> x₁ x₂)
-si-property-< ne ti (s-left _ _ _ x (s-right .(node _ _ _ _) _ tree₁ x₁ si)) = x
-si-property-< ne ti (s-left _ _ _ x (s-left .(node _ _ _ _) _ tree₁ x₁ si)) = x
-si-property-< ne ti (s-left _ _ _ x s-nil) = x
-si-property-< ne (t-single _ _) (s-right _ _ tree₁ x si) = ⊥-elim ( ne refl )
-
-si-property-> :  {n : Level} {A : Set n} {key kp : ℕ} {value₂ : A} {tree orig tree₃ : bt A} → {stack  : List (bt A)}
-   → ¬ ( tree ≡ leaf )
-   → treeInvariant (node kp value₂ tree₃  tree )
-   → stackInvariant key tree orig (tree ∷ node kp value₂ tree₃  tree ∷ stack)
-   → kp < key
-si-property-> ne ti (s-right _ _ tree₁ x s-nil) = x
-si-property-> ne ti (s-right _ _ tree₁ x (s-right .(node _ _ tree₁ _) _ tree₂ x₁ si)) = x
-si-property-> ne ti (s-right _ _ tree₁ x (s-left .(node _ _ tree₁ _) _ tree x₁ si)) = x
-si-property-> ne (t-node _ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (s-left _ _ _ x s-nil) = ⊥-elim (nat-<> x₁ x₂)
-si-property-> ne (t-node _ _ _ x₂ x₃ x₄ x₅ x₆ x₇ ti ti₁) (s-left _ _ _ x (s-right .(node _ _ _ _) _ tree₁ x₁ si)) = ⊥-elim (nat-<> x₂ x₃)
-si-property-> ne (t-node _ _ _ x₂ x₃ x₄ x₅ x₆ x₇ ti ti₁) (s-left _ _ _ x (s-left .(node _ _ _ _) _ tree x₁ si)) = ⊥-elim (nat-<> x₂ x₃)
-si-property-> ne (t-single _ _) (s-left _ _ _ x s-nil) = ⊥-elim ( ne refl )
-si-property-> ne (t-single _ _) (s-left _ _ _ x (s-right .(node _ _ leaf leaf) _ tree₁ x₁ si)) = ⊥-elim ( ne refl )
-si-property-> ne (t-single _ _) (s-left _ _ _ x (s-left .(node _ _ leaf leaf) _ tree x₁ si)) = ⊥-elim ( ne refl )
-
-si-property-last :  {n : Level} {A : Set n}  (key : ℕ) (tree tree0 : bt A) → (stack  : List (bt A)) →  stackInvariant key tree tree0 stack
-   → stack-last stack ≡ just tree0
-si-property-last key t t0 (t ∷ [])  (s-nil )  = refl
-si-property-last key t t0 (.t ∷ x ∷ st) (s-right _ _ _ _ si ) with  si-property1 si
-... | refl = si-property-last key x t0 (x ∷ st)   si
-si-property-last key t t0 (.t ∷ x ∷ st) (s-left _ _ _ _ si ) with  si-property1  si
-... | refl = si-property-last key x t0 (x ∷ st)   si
-
-si-property-pne :  {n : Level} {A : Set n}  {key key₁ : ℕ} {value₁ : A} (tree orig : bt A) → {left right x : bt A} → (stack  : List (bt A)) {rest : List (bt A)}
-    → stack ≡ x ∷ node key₁ value₁ left right ∷ rest
-    → stackInvariant key tree orig stack
-    → ¬ ( key ≡ key₁ )
-si-property-pne tree orig .(tree ∷ node _ _ _ _ ∷ _) refl (s-right .tree .orig tree₁ x si) eq with si-property1 si
-... | refl = ⊥-elim ( nat-≡< (sym eq) x)
-si-property-pne tree orig .(tree ∷ node _ _ _ _ ∷ _) refl (s-left .tree .orig tree₁ x si) eq with si-property1 si
-... | refl = ⊥-elim ( nat-≡< eq x)
-
-si-property-parent-node :  {n : Level} {A : Set n}  {key : ℕ}  (tree orig : bt A) {x : bt A}
-    → (stack  : List (bt A)) {rest : List (bt A)}
-    → stackInvariant key tree orig stack
-    → ¬ ( stack ≡ x ∷ leaf ∷ rest )
-si-property-parent-node {n} {A} tree orig .(tree ∷ leaf ∷ _) (s-right .tree .orig tree₁ x si) refl with si-property1 si
-... | ()
-si-property-parent-node {n} {A} tree orig .(tree ∷ leaf ∷ _) (s-left .tree .orig tree₁ x si) refl with si-property1 si
-... | ()
-
-
-rt-property1 :  {n : Level} {A : Set n} (key : ℕ) (value : A) (tree tree1 : bt A ) → replacedTree key value tree tree1 → ¬ ( tree1 ≡ leaf )
-rt-property1 {n} {A} key value .leaf .(node key value leaf leaf) r-leaf ()
-rt-property1 {n} {A} key value .(node key _ _ _) .(node key value _ _) r-node ()
-rt-property1 {n} {A} key value .(node _ _ _ _) _ (r-right x rt) = λ ()
-rt-property1 {n} {A} key value .(node _ _ _ _) _ (r-left x rt) = λ ()
-
-rt-property-leaf : {n : Level} {A : Set n} {key : ℕ} {value : A} {repl : bt A} → replacedTree key value leaf repl → repl ≡ node key value leaf leaf
-rt-property-leaf r-leaf = refl
-
-rt-property-¬leaf : {n : Level} {A : Set n} {key : ℕ} {value : A} {tree : bt A} → ¬ replacedTree key value tree leaf
-rt-property-¬leaf ()
-
-rt-property-key : {n : Level} {A : Set n} {key key₂ key₃ : ℕ} {value value₂ value₃ : A} {left left₁ right₂ right₃ : bt A}
-    →  replacedTree key value (node key₂ value₂ left right₂) (node key₃ value₃ left₁ right₃) → key₂ ≡ key₃
-rt-property-key r-node = refl
-rt-property-key (r-right x ri) = refl
-rt-property-key (r-left x ri) = refl
-
-
-open _∧_
-
-
-depth-1< : {i j : ℕ} →   suc i ≤ suc (i Data.Nat.⊔ j )
-depth-1< {i} {j} = s≤s (m≤m⊔n _ j)
-
-depth-2< : {i j : ℕ} →   suc i ≤ suc (j Data.Nat.⊔ i )
-depth-2< {i} {j} = s≤s (m≤n⊔m j i)
-
-depth-3< : {i : ℕ } → suc i ≤ suc (suc i)
-depth-3< {zero} = s≤s ( z≤n )
-depth-3< {suc i} = s≤s (depth-3< {i} )
-
-
-treeLeftDown  : {n : Level} {A : Set n} {k : ℕ} {v1 : A}  → (tree tree₁ : bt A )
-      → treeInvariant (node k v1 tree tree₁)
-      →      treeInvariant tree
-treeLeftDown {n} {A} {_} {v1} leaf leaf (t-single k1 v1) = t-leaf
-treeLeftDown {n} {A} {_} {v1} .leaf .(node _ _ _ _) (t-right _ _ x _ _ ti) = t-leaf
-treeLeftDown {n} {A} {_} {v1} .(node _ _ _ _) .leaf (t-left _ _ x _ _ ti) = ti
-treeLeftDown {n} {A} {_} {v1} .(node _ _ _ _) .(node _ _ _ _) (t-node _ _ _ x x₁ _ _ _ _ ti ti₁) = ti
-
-treeRightDown  : {n : Level} {A : Set n} {k : ℕ} {v1 : A}  → (tree tree₁ : bt A )
-      → treeInvariant (node k v1 tree tree₁)
-      →      treeInvariant tree₁
-treeRightDown {n} {A} {_} {v1} .leaf .leaf (t-single _ .v1) = t-leaf
-treeRightDown {n} {A} {_} {v1} .leaf .(node _ _ _ _) (t-right _ _ x _ _ ti) = ti
-treeRightDown {n} {A} {_} {v1} .(node _ _ _ _) .leaf (t-left _ _ x _ _ ti) = t-leaf
-treeRightDown {n} {A} {_} {v1} .(node _ _ _ _) .(node _ _ _ _) (t-node _ _ _ x x₁ _ _ _ _ ti ti₁) = ti₁
-
-ti-property1 :  {n : Level} {A : Set n} {key₁ : ℕ} {value₂ : A} {left right : bt A} → treeInvariant (node key₁ value₂  left right ) →   tr< key₁ left ∧  tr> key₁ right
-ti-property1 {n} {A} {key₁} {value₂} {.leaf} {.leaf} (t-single .key₁ .value₂) = ⟪ tt , tt ⟫
-ti-property1 {n} {A} {key₁} {value₂} {.leaf} {.(node key₂ _ _ _)} (t-right .key₁ key₂ x x₁ x₂ t) = ⟪ tt , ⟪ x , ⟪ x₁ , x₂ ⟫ ⟫ ⟫
-ti-property1 {n} {A} {key₁} {value₂} {.(node key _ _ _)} {.leaf} (t-left key .key₁ x x₁ x₂ t) = ⟪ ⟪ x , ⟪ x₁ , x₂ ⟫ ⟫ , tt ⟫
-ti-property1 {n} {A} {key₁} {value₂} {.(node key _ _ _)} {.(node key₂ _ _ _)} (t-node key .key₁ key₂ x x₁ x₂ x₃ x₄ x₅ t t₁) 
-     = ⟪ ⟪ x , ⟪ x₂ , x₃ ⟫ ⟫ , ⟪ x₁ , ⟪ x₄ , x₅ ⟫ ⟫ ⟫
-
-
-findP : {n m : Level} {A : Set n} {t : Set m} → (key : ℕ) → (tree tree0 : bt A ) → (stack : List (bt A))
-           →  treeInvariant tree ∧ stackInvariant key tree tree0 stack
-           → (next : (tree1 : bt A) → (stack : List (bt A)) → treeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack → bt-depth tree1 < bt-depth tree   → t )
-           → (exit : (tree1 : bt A) → (stack : List (bt A)) → treeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
-                 → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )  → t ) → t
-findP key leaf tree0 st Pre _ exit = exit leaf st Pre (case1 refl)
-findP key (node key₁ v1 tree tree₁) tree0 st Pre next exit with <-cmp key key₁
-findP key n tree0 st Pre _ exit | tri≈ ¬a refl ¬c = exit n st Pre (case2 refl)
-findP {n} {_} {A} key (node key₁ v1 tree tree₁) tree0 st  Pre next _ | tri< a ¬b ¬c = next tree (tree ∷ st)
-       ⟪ treeLeftDown tree tree₁ (proj1 Pre)  , findP1 a st (proj2 Pre) ⟫ depth-1< where
-   findP1 : key < key₁ → (st : List (bt A)) →  stackInvariant key (node key₁ v1 tree tree₁) tree0 st → stackInvariant key tree tree0 (tree ∷ st)
-   findP1 a (x ∷ st) si = s-left _ _ _ a si
-findP key n@(node key₁ v1 tree tree₁) tree0 st Pre next _ | tri> ¬a ¬b c = next tree₁ (tree₁ ∷ st) ⟪ treeRightDown tree tree₁ (proj1 Pre) , s-right _ _ _ c (proj2 Pre) ⟫ depth-2<
-
-replaceTree1 : {n  : Level} {A : Set n} {t t₁ : bt A } → ( k : ℕ ) → (v1 value : A ) →  treeInvariant (node k v1 t t₁) → treeInvariant (node k value t t₁)
-replaceTree1 k v1 value (t-single .k .v1) = t-single k value
-replaceTree1 k v1 value (t-right _ _ x a b t) = t-right _ _ x a b t
-replaceTree1 k v1 value (t-left _ _ x a b t) = t-left _ _ x a b t
-replaceTree1 k v1 value (t-node _ _ _ x x₁ a b c d t t₁) = t-node _ _ _ x x₁ a b c d t t₁
-
-open import Relation.Binary.Definitions
-
-lemma3 : {i j : ℕ} → 0 ≡ i → j < i → ⊥
-lemma3 refl ()
-lemma5 : {i j : ℕ} → i < 1 → j < i → ⊥
-lemma5 (s≤s z≤n) ()
-¬x<x : {x : ℕ} → ¬ (x < x)
-¬x<x (s≤s lt) = ¬x<x lt
-
-child-replaced :  {n : Level} {A : Set n} (key : ℕ)   (tree : bt A) → bt A
-child-replaced key leaf = leaf
-child-replaced key (node key₁ value left right) with <-cmp key key₁
-... | tri< a ¬b ¬c = left
-... | tri≈ ¬a b ¬c = node key₁ value left right
-... | tri> ¬a ¬b c = right
-
-child-replaced-left :  {n : Level} {A : Set n} {key key₁ : ℕ}  {value : A}  {left right : bt A}
-   → key < key₁
-   → child-replaced key (node key₁ value left right) ≡ left
-child-replaced-left {n} {A} {key} {key₁} {value} {left} {right} lt = ch00 (node key₁ value left right) refl lt where
-     ch00 : (tree : bt A) → tree ≡ node key₁ value left right → key < key₁ → child-replaced key tree ≡ left
-     ch00 (node key₁ value tree tree₁) refl lt1 with <-cmp key key₁
-     ... | tri< a ¬b ¬c = refl
-     ... | tri≈ ¬a b ¬c = ⊥-elim (¬a lt1)
-     ... | tri> ¬a ¬b c = ⊥-elim (¬a lt1)
-
-child-replaced-right :  {n : Level} {A : Set n} {key key₁ : ℕ}  {value : A}  {left right : bt A}
-   → key₁ < key
-   → child-replaced key (node key₁ value left right) ≡ right
-child-replaced-right {n} {A} {key} {key₁} {value} {left} {right} lt = ch00 (node key₁ value left right) refl lt where
-     ch00 : (tree : bt A) → tree ≡ node key₁ value left right → key₁ < key → child-replaced key tree ≡ right
-     ch00 (node key₁ value tree tree₁) refl lt1 with <-cmp key key₁
-     ... | tri< a ¬b ¬c = ⊥-elim (¬c lt1)
-     ... | tri≈ ¬a b ¬c = ⊥-elim (¬c lt1)
-     ... | tri> ¬a ¬b c = refl
-
-child-replaced-eq :  {n : Level} {A : Set n} {key key₁ : ℕ}  {value : A}  {left right : bt A}
-   → key₁ ≡ key
-   → child-replaced key (node key₁ value left right) ≡ node key₁ value left right
-child-replaced-eq {n} {A} {key} {key₁} {value} {left} {right} lt = ch00 (node key₁ value left right) refl lt where
-     ch00 : (tree : bt A) → tree ≡ node key₁ value left right → key₁ ≡ key → child-replaced key tree ≡ node key₁ value left right
-     ch00 (node key₁ value tree tree₁) refl lt1 with <-cmp key key₁
-     ... | tri< a ¬b ¬c = ⊥-elim (¬b (sym lt1))
-     ... | tri≈ ¬a b ¬c = refl
-     ... | tri> ¬a ¬b c = ⊥-elim (¬b (sym lt1))
-
-record replacePR {n : Level} {A : Set n} (key : ℕ) (value : A) (tree repl : bt A ) (stack : List (bt A)) (C : bt A → bt A → List (bt A) → Set n) : Set n where
-   field
-     tree0 : bt A
-     ti : treeInvariant tree0
-     si : stackInvariant key tree tree0 stack
-     ri : replacedTree key value (child-replaced key tree ) repl
-     ci : C tree repl stack     -- data continuation
-
-record replacePR' {n : Level} {A : Set n} (key : ℕ) (value : A) (orig : bt A ) (stack : List (bt A))  : Set n where
-   field
-     tree repl : bt A
-     ti : treeInvariant orig
-     si : stackInvariant key tree orig stack
-     ri : replacedTree key value (child-replaced key tree) repl
-     --   treeInvariant of tree and repl is inferred from ti, si and ri.
-
-replaceNodeP : {n m : Level} {A : Set n} {t : Set m} → (key : ℕ) → (value : A) → (tree : bt A)
-    → (tree ≡ leaf ) ∨ ( node-key tree ≡ just key )
-    → (treeInvariant tree ) → ((tree1 : bt A) → treeInvariant tree1 →  replacedTree key value (child-replaced key tree) tree1 → t) → t
-replaceNodeP k v1 leaf C P next = next (node k v1 leaf leaf) (t-single k v1 ) r-leaf
-replaceNodeP k v1 (node .k value t t₁) (case2 refl) P next = next (node k v1 t t₁) (replaceTree1 k value v1 P)
-     (subst (λ j → replacedTree k v1 j  (node k v1 t t₁) ) repl00 r-node) where
-         repl00 : node k value t t₁ ≡ child-replaced k (node k value t t₁)
-         repl00 with <-cmp k k
-         ... | tri< a ¬b ¬c = ⊥-elim (¬b refl)
-         ... | tri≈ ¬a b ¬c = refl
-         ... | tri> ¬a ¬b c = ⊥-elim (¬b refl)
-
-replaceP : {n m : Level} {A : Set n} {t : Set m}
-     → (key : ℕ) → (value : A) → {tree : bt A} ( repl : bt A)
-     → (stack : List (bt A)) → replacePR key value tree repl stack (λ _ _ _ → Lift n ⊤)
-     → (next : ℕ → A → {tree1 : bt A } (repl : bt A) → (stack1 : List (bt A))
-         → replacePR key value tree1 repl stack1 (λ _ _ _ → Lift n ⊤) → length stack1 < length stack → t)
-     → (exit : (tree1 repl : bt A) → treeInvariant tree1 ∧ replacedTree key value tree1 repl → t) → t
-replaceP = ?
-
-TerminatingLoopS : {l m : Level} {t : Set l} (Index : Set m ) → {Invraiant : Index → Set m } → ( reduce : Index → ℕ)
-   → (r : Index) → (p : Invraiant r)
-   → (loop : (r : Index)  → Invraiant r → (next : (r1 : Index)  → Invraiant r1 → reduce r1 < reduce r  → t ) → t) → t
-TerminatingLoopS {_} {_} {t} Index {Invraiant} reduce r p loop with <-cmp 0 (reduce r)
-... | tri≈ ¬a b ¬c = loop r p (λ r1 p1 lt → ⊥-elim (lemma3 b lt) )
-... | tri< a ¬b ¬c = loop r p (λ r1 p1 lt1 → TerminatingLoop1 (reduce r) r r1 (m≤n⇒m≤1+n lt1) p1 lt1 ) where
-    TerminatingLoop1 : (j : ℕ) → (r r1 : Index) → reduce r1 < suc j  → Invraiant r1 →  reduce r1 < reduce r → t
-    TerminatingLoop1 zero r r1 n≤j p1 lt = loop r1 p1 (λ r2 p1 lt1 → ⊥-elim (lemma5 n≤j lt1))
-    TerminatingLoop1 (suc j) r r1  n≤j p1 lt with <-cmp (reduce r1) (suc j)
-    ... | tri< a ¬b ¬c = TerminatingLoop1 j r r1 a p1 lt
-    ... | tri≈ ¬a b ¬c = loop r1 p1 (λ r2 p2 lt1 → TerminatingLoop1 j r1 r2 (subst (λ k → reduce r2 < k ) b lt1 ) p2 lt1 )
-    ... | tri> ¬a ¬b c =  ⊥-elim ( nat-≤> c n≤j )
-
-open _∧_
-
-ri-tr>  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key key₁ : ℕ) → (value : A)
-     → replacedTree key value tree repl → key₁ < key → tr> key₁ tree → tr> key₁ repl
-ri-tr> .leaf .(node key value leaf leaf) key key₁ value r-leaf a tgt = ⟪ a , ⟪ tt , tt ⟫ ⟫
-ri-tr> .(node key _ _ _) .(node key value _ _) key key₁ value r-node a tgt = ⟪ a , ⟪ proj1 (proj2 tgt) , proj2 (proj2 tgt) ⟫ ⟫
-ri-tr> .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-right x ri) a tgt = ⟪ proj1 tgt , ⟪ proj1 (proj2 tgt) , ri-tr> _ _ _ _ _ ri a (proj2 (proj2 tgt)) ⟫ ⟫
-ri-tr> .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-left x ri) a tgt = ⟪ proj1 tgt , ⟪  ri-tr> _ _ _ _ _ ri a (proj1 (proj2 tgt)) , proj2 (proj2 tgt)  ⟫ ⟫
-
-ri-tr<  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key key₁ : ℕ) → (value : A)
-     → replacedTree key value tree repl → key < key₁ → tr< key₁ tree → tr< key₁ repl
-ri-tr< .leaf .(node key value leaf leaf) key key₁ value r-leaf a tgt = ⟪ a , ⟪ tt , tt ⟫ ⟫
-ri-tr< .(node key _ _ _) .(node key value _ _) key key₁ value r-node a tgt = ⟪ a , ⟪ proj1 (proj2 tgt) , proj2 (proj2 tgt) ⟫ ⟫
-ri-tr< .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-right x ri) a tgt = ⟪ proj1 tgt , ⟪ proj1 (proj2 tgt) , ri-tr< _ _ _ _ _ ri a (proj2 (proj2 tgt)) ⟫ ⟫
-ri-tr< .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-left x ri) a tgt = ⟪ proj1 tgt , ⟪  ri-tr< _ _ _ _ _ ri a (proj1 (proj2 tgt)) , proj2 (proj2 tgt)  ⟫ ⟫
-
-<-tr>  : {n : Level} {A : Set n}  → {tree : bt A} → {key₁ key₂ : ℕ} → tr> key₁ tree → key₂ < key₁  → tr> key₂ tree
-<-tr> {n} {A} {leaf} {key₁} {key₂} tr lt = tt
-<-tr> {n} {A} {node key value t t₁} {key₁} {key₂} tr lt = ⟪ <-trans lt (proj1 tr) , ⟪ <-tr> (proj1 (proj2 tr)) lt , <-tr> (proj2 (proj2 tr)) lt ⟫ ⟫
-
->-tr<  : {n : Level} {A : Set n}  → {tree : bt A} → {key₁ key₂ : ℕ} → tr< key₁ tree → key₁ < key₂  → tr< key₂ tree
->-tr<  {n} {A} {leaf} {key₁} {key₂} tr lt = tt
->-tr<  {n} {A} {node key value t t₁} {key₁} {key₂} tr lt = ⟪ <-trans (proj1 tr) lt , ⟪ >-tr< (proj1 (proj2 tr)) lt , >-tr< (proj2 (proj2 tr)) lt ⟫ ⟫
-
-RTtoTI0  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key : ℕ) → (value : A) → treeInvariant tree
-     → replacedTree key value tree repl → treeInvariant repl
-RTtoTI0 .leaf .(node key value leaf leaf) key value ti r-leaf = t-single key value
-RTtoTI0 .(node key _ leaf leaf) .(node key value leaf leaf) key value (t-single .key _) r-node = t-single key value
-RTtoTI0 .(node key _ leaf (node _ _ _ _)) .(node key value leaf (node _ _ _ _)) key value (t-right _ _ x a b ti) r-node = t-right _ _ x a b ti
-RTtoTI0 .(node key _ (node _ _ _ _) leaf) .(node key value (node _ _ _ _) leaf) key value (t-left _ _ x a b ti) r-node = t-left _ _ x a b ti
-RTtoTI0 .(node key _ (node _ _ _ _) (node _ _ _ _)) .(node key value (node _ _ _ _) (node _ _ _ _)) key value (t-node _ _ _ x x₁ a b c d ti ti₁) r-node = t-node _ _ _ x x₁ a b c d ti ti₁
--- r-right case
-RTtoTI0 (node _ _ leaf leaf) (node _ _ leaf .(node key value leaf leaf)) key value (t-single _ _) (r-right x r-leaf) = t-right _ _ x _ _ (t-single key value)
-RTtoTI0 (node _ _ leaf right@(node _ _ _ _)) (node key₁ value₁ leaf leaf) key value (t-right _ _ x₁ a b ti) (r-right x ri) = t-single key₁ value₁
-RTtoTI0 (node key₁ _ leaf right@(node key₂ _ left₁ right₁)) (node key₁ value₁ leaf right₃@(node key₃ _ left₂ right₂)) key value (t-right key₄ key₅ x₁ a b ti) (r-right x ri) =
-      t-right _ _ (subst (λ k → key₁ < k ) (rt-property-key ri) x₁) (rr00 ri a ) (rr02 ri b) (RTtoTI0 right right₃ key value ti ri) where
-         rr00 : replacedTree key value (node key₂ _ left₁ right₁) (node key₃ _ left₂ right₂) → tr> key₁ left₁ → tr> key₁ left₂
-         rr00 r-node tb = tb
-         rr00 (r-right x ri) tb = tb
-         rr00 (r-left x₂ ri) tb = ri-tr> _ _ _ _ _ ri x tb
-         rr02 : replacedTree key value (node key₂ _ left₁ right₁) (node key₃ _ left₂ right₂) → tr> key₁ right₁ → tr> key₁ right₂
-         rr02 r-node tb = tb
-         rr02 (r-right x₂ ri) tb = ri-tr> _ _ _ _ _ ri x tb
-         rr02 (r-left x ri) tb = tb
-RTtoTI0 (node key₁ _ (node _ _ _ _) leaf) (node key₁ _ (node key₃ value left right) leaf) key value₁ (t-left _ _ x₁ a b ti) (r-right x ())
-RTtoTI0 (node key₁ _ (node key₃ _ _ _) leaf) (node key₁ _ (node key₃ value₃ _ _) (node key value leaf leaf)) key value (t-left _ _ x₁ a b ti) (r-right x r-leaf) =
-      t-node _ _ _ x₁ x a b tt tt ti (t-single key value)
-RTtoTI0 (node key₁ _ (node _ _ left₀ right₀) (node key₂ _ left₁ right₁)) (node key₁ _ (node _ _ left₂ right₂) (node key₃ _ left₃ right₃)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-right x ri) =
-      t-node _ _ _ x₁ (subst (λ k → key₁ < k ) (rt-property-key ri) x₂) a b (rr00 ri c) (rr02 ri d) ti (RTtoTI0 _ _ key value ti₁ ri) where
-         rr00 : replacedTree key value (node key₂ _ _ _) (node key₃ _ _ _) → tr> key₁ left₁ → tr> key₁ left₃
-         rr00 r-node tb = tb
-         rr00 (r-right x₃ ri) tb = tb
-         rr00 (r-left x₃ ri) tb = ri-tr> _ _ _ _ _ ri x tb
-         rr02 : replacedTree key value (node key₂ _ _ _) (node key₃ _ _ _) → tr> key₁ right₁ → tr> key₁ right₃
-         rr02 r-node tb = tb
-         rr02 (r-right x₃ ri) tb = ri-tr> _ _ _ _ _ ri x tb
-         rr02 (r-left x₃ ri) tb = tb
--- r-left case
-RTtoTI0 .(node _ _ leaf leaf) .(node _ _ (node key value leaf leaf) leaf) key value (t-single _ _) (r-left x r-leaf) = t-left _ _ x tt tt (t-single _ _ )
-RTtoTI0 .(node _ _ leaf (node _ _ _ _)) (node key₁ value₁ (node key value leaf leaf) (node _ _ _ _)) key value (t-right _ _ x₁ a b ti) (r-left x r-leaf) =
-      t-node _ _ _ x x₁ tt tt a b (t-single key value) ti
-RTtoTI0 (node key₃ _ (node key₂ _ left₁ right₁) leaf) (node key₃ _ (node key₁ value₁ left₂ right₂) leaf) key value (t-left _ _ x₁ a b ti) (r-left x ri) =
-      t-left _ _ (subst (λ k → k < key₃ ) (rt-property-key ri) x₁) (rr00 ri a) (rr02 ri b) (RTtoTI0 _ _ key value ti ri) where -- key₁ < key₃
-         rr00 : replacedTree key value (node key₂ _ left₁ right₁) (node key₁ _ left₂ right₂) → tr< key₃ left₁ → tr< key₃ left₂
-         rr00 r-node tb = tb
-         rr00 (r-right x₂ ri) tb = tb
-         rr00 (r-left x₂ ri) tb = ri-tr< _ _ _ _ _ ri x tb
-         rr02 : replacedTree key value (node key₂ _ left₁ right₁) (node key₁ _ left₂ right₂) → tr< key₃ right₁ → tr< key₃ right₂
-         rr02 r-node tb = tb
-         rr02 (r-right x₃ ri) tb = ri-tr< _ _ _ _ _ ri x tb
-         rr02 (r-left x₃ ri) tb = tb
-RTtoTI0 (node key₁ _ (node key₂ _ left₂ right₂) (node key₃ _ left₃ right₃)) (node key₁ _ (node key₄ _ left₄ right₄) (node key₅ _ left₅ right₅)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-left x ri) =
-      t-node _ _ _ (subst (λ k → k < key₁ ) (rt-property-key ri) x₁) x₂  (rr00 ri a) (rr02 ri b) c d (RTtoTI0 _ _ key value ti ri) ti₁ where
-         rr00 : replacedTree key value (node key₂ _ left₂ right₂) (node key₄ _ left₄ right₄) → tr< key₁ left₂ → tr< key₁ left₄
-         rr00 r-node tb = tb
-         rr00 (r-right x₃ ri) tb = tb
-         rr00 (r-left x₃ ri) tb = ri-tr< _ _ _ _ _ ri x tb
-         rr02 : replacedTree key value (node key₂ _ left₂ right₂) (node key₄ _ left₄ right₄) → tr< key₁ right₂ → tr< key₁ right₄
-         rr02 r-node tb = tb
-         rr02 (r-right x₃ ri) tb = ri-tr< _ _ _ _ _ ri x tb
-         rr02 (r-left x₃ ri) tb = tb
-
--- RTtoTI1  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key : ℕ) → (value : A) → treeInvariant repl
---      → replacedTree key value tree repl → treeInvariant tree
--- RTtoTI1 .leaf .(node key value leaf leaf) key value ti r-leaf = t-leaf
--- RTtoTI1 (node key value₁ leaf leaf) .(node key value leaf leaf) key value (t-single .key .value) r-node = t-single key value₁
--- RTtoTI1 .(node key _ leaf (node _ _ _ _)) .(node key value leaf (node _ _ _ _)) key value (t-right _ _ x a b ti) r-node = t-right _ _ x a b ti
--- RTtoTI1 .(node key _ (node _ _ _ _) leaf) .(node key value (node _ _ _ _) leaf) key value (t-left _ _ x a b ti) r-node = t-left _ _ x a b ti
--- RTtoTI1 .(node key _ (node _ _ _ _) (node _ _ _ _)) .(node key value (node _ _ _ _) (node _ _ _ _)) key value (t-node _ _ _ x x₁ a b c d ti ti₁) r-node = t-node _ _ _ x x₁ a b c d ti ti₁
--- -- r-right case
--- RTtoTI1 (node key₁ value₁ leaf leaf) (node key₁ _ leaf (node _ _ _ _)) key value (t-right _ _ x₁ a b ti) (r-right x r-leaf) = t-single key₁ value₁
--- RTtoTI1 (node key₁ value₁ leaf (node key₂ value₂ t2 t3)) (node key₁ _ leaf (node key₃ _ _ _)) key value (t-right _ _ x₁ a b ti) (r-right x ri) =
---    t-right _ _ (subst (λ k → key₁ < k ) (sym (rt-property-key ri)) x₁) ? ?  (RTtoTI1 _ _ key value ti ri) -- key₁ < key₂
--- RTtoTI1 (node _ _ (node _ _ _ _) leaf) (node _ _ (node _ _ _ _) (node key value _ _)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-right x r-leaf) =
---     t-left _ _ x₁ ? ? ti
--- RTtoTI1 (node key₄ _ (node key₃ _ _ _) (node key₁ value₁ n n₁)) (node key₄ _ (node key₃ _ _ _) (node key₂ _ _ _)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-right x ri) = t-node _ _ _ x₁ (subst (λ k → key₄ < k ) (sym (rt-property-key ri)) x₂) a b ? ? ti (RTtoTI1 _ _ key value ti₁ ri) -- key₄ < key₁
--- -- r-left case
--- RTtoTI1 (node key₁ value₁ leaf leaf) (node key₁ _ _ leaf) key value (t-left _ _ x₁ a b ti) (r-left x ri) = t-single key₁ value₁
--- RTtoTI1 (node key₁ _ (node key₂ value₁ n n₁) leaf) (node key₁ _ (node key₃ _ _ _) leaf) key value (t-left _ _ x₁ a b ti) (r-left x ri) =
---    t-left _ _ (subst (λ k → k < key₁ ) (sym (rt-property-key ri)) x₁) ? ? (RTtoTI1 _ _ key value ti ri) -- key₂ < key₁
--- RTtoTI1 (node key₁ value₁ leaf _) (node key₁ _ _ _) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-left x r-leaf) = t-right _ _ x₂ c d ti₁
--- RTtoTI1 (node key₁ value₁ (node key₂ value₂ n n₁) _) (node key₁ _ _ _) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-left x ri) =
---     t-node _ _ _ (subst (λ k → k < key₁ ) (sym (rt-property-key ri)) x₁) x₂ ? ? c d (RTtoTI1 _ _ key value ti ri) ti₁ -- key₂ < key₁
-
-insertTreeP : {n m : Level} {A : Set n} {t : Set m} → (tree : bt A) → (key : ℕ) → (value : A) → treeInvariant tree
-     → (exit : (tree repl : bt A) → treeInvariant repl ∧ replacedTree key value tree repl → t ) → t
-insertTreeP {n} {m} {A} {t} tree key value P0 exit =
-   TerminatingLoopS (bt A ∧ List (bt A) ) {λ p → treeInvariant (proj1 p) ∧ stackInvariant key (proj1 p) tree (proj2 p) } (λ p → bt-depth (proj1 p)) ⟪ tree , tree ∷ [] ⟫  ⟪ P0 , s-nil ⟫
-       $ λ p P loop → findP key (proj1 p)  tree (proj2 p) P (λ t s P1 lt → loop ⟪ t ,  s  ⟫ P1 lt )
-       $ λ t s P C → replaceNodeP key value t C (proj1 P)
-       $ λ t1 P1 R → TerminatingLoopS (List (bt A) ∧ bt A ∧ bt A )
-            {λ p → replacePR key value  (proj1 (proj2 p)) (proj2 (proj2 p)) (proj1 p)  (λ _ _ _ → Lift n ⊤ ) }
-               (λ p → length (proj1 p)) ⟪ s , ⟪ t , t1 ⟫ ⟫ record { tree0 = tree ; ti = P0 ; si = proj2 P ; ri = R ; ci = lift tt }
-       $  λ p P1 loop → replaceP key value  (proj2 (proj2 p)) (proj1 p) P1
-            (λ key value {tree1} repl1 stack P2 lt → loop ⟪ stack , ⟪ tree1 , repl1  ⟫ ⟫ P2 lt )
-       $ λ tree repl P → exit tree repl ⟪ RTtoTI0 _ _ _ _ (proj1 P) (proj2 P) , proj2 P ⟫
-
-insertTestP1 = insertTreeP leaf 1 1 t-leaf
-  $ λ _ x0 P0 → insertTreeP x0 2 1 (proj1 P0)
-  $ λ _ x1 P1 → insertTreeP x1 3 2 (proj1 P1)
-  $ λ _ x2 P2 → insertTreeP x2 2 2 (proj1 P2) (λ _ x P  → x )
-
-top-value : {n : Level} {A : Set n} → (tree : bt A) →  Maybe A
-top-value leaf = nothing
-top-value (node key value tree tree₁) = just value
-
--- is realy inserted?
-
--- other element is preserved?
-
--- deletion?
-
-
-data Color  : Set where
-    Red : Color
-    Black : Color
-
-RB→bt : {n : Level} (A : Set n) → (bt (Color ∧ A)) → bt A
-RB→bt {n} A leaf = leaf
-RB→bt {n} A (node key ⟪ C , value ⟫ tr t1) = (node key value (RB→bt A tr) (RB→bt A t1))
-
-color : {n : Level} {A : Set n} → (bt (Color ∧ A)) → Color
-color leaf = Black
-color (node key ⟪ C , value ⟫ rb rb₁) = C
-
-to-red : {n : Level} {A : Set n} → (tree : bt (Color ∧ A)) → bt (Color ∧ A)
-to-red leaf = leaf
-to-red (node key ⟪ _ , value ⟫ t t₁) = (node key ⟪ Red , value ⟫ t t₁)
-
-to-black : {n : Level} {A : Set n} → (tree : bt (Color ∧ A)) → bt (Color ∧ A)
-to-black leaf = leaf
-to-black (node key ⟪ _ , value ⟫ t t₁) = (node key ⟪ Black , value ⟫ t t₁)
-
-black-depth : {n : Level} {A : Set n} → (tree : bt (Color ∧ A) ) → ℕ
-black-depth leaf = 1
-black-depth (node key ⟪ Red , value ⟫  t t₁) = black-depth t  ⊔ black-depth t₁
-black-depth (node key ⟪ Black , value ⟫  t t₁) = suc (black-depth t  ⊔ black-depth t₁ )
-
-zero≢suc : { m : ℕ } → zero ≡ suc m → ⊥
-zero≢suc ()
-suc≢zero : {m : ℕ } → suc m ≡ zero → ⊥
-suc≢zero ()
-
-data RBtreeInvariant {n : Level} {A : Set n} : (tree : bt (Color ∧ A)) → Set n where
-    rb-leaf :  RBtreeInvariant leaf
-    rb-red :  (key : ℕ) → (value : A) → {left right : bt (Color ∧ A)}
-       → color left ≡ Black → color right ≡ Black
-       → black-depth left ≡ black-depth right
-       → RBtreeInvariant left → RBtreeInvariant right
-       → RBtreeInvariant (node key ⟪ Red , value ⟫ left right)
-    rb-black :  (key : ℕ) → (value : A) → {left right : bt (Color ∧ A)}
-       → black-depth left ≡ black-depth right
-       → RBtreeInvariant left → RBtreeInvariant right
-       → RBtreeInvariant (node key ⟪ Black , value ⟫ left right)
-
-RightDown : {n : Level} {A : Set n} → bt (Color ∧ A) → bt (Color ∧ A)
-RightDown leaf = leaf
-RightDown (node key ⟪ c , value ⟫ t1 t2) = t2
-LeftDown : {n : Level} {A :  Set n} → bt (Color ∧ A) → bt (Color ∧ A)
-LeftDown leaf = leaf
-LeftDown (node key ⟪ c , value ⟫ t1 t2 ) = t1
-
-RBtreeLeftDown : {n : Level} {A : Set n} {key : ℕ} {value : A} {c : Color}
- →  (left right : bt (Color ∧ A))
- → RBtreeInvariant (node key ⟪ c , value ⟫ left right)
- → RBtreeInvariant left
-RBtreeLeftDown left right (rb-red _ _ x x₁ x₂ rb rb₁) = rb
-RBtreeLeftDown left right (rb-black _ _ x rb rb₁) = rb
-
-
-RBtreeRightDown : {n : Level} {A : Set n} { key : ℕ} {value : A} {c : Color}
- → (left right : bt (Color ∧ A))
- → RBtreeInvariant (node key ⟪ c , value ⟫ left right)
- → RBtreeInvariant right
-RBtreeRightDown left right (rb-red _ _ x x₁ x₂ rb rb₁) = rb₁
-RBtreeRightDown left right (rb-black _ _ x rb rb₁) = rb₁
-
-RBtreeEQ : {n : Level} {A : Set n} {key : ℕ} {value : A} {c : Color}
- → {left right : bt (Color ∧ A)}
- → RBtreeInvariant (node key ⟪ c , value ⟫ left right)
- → black-depth left ≡ black-depth right
-RBtreeEQ  (rb-red _ _ x x₁ x₂ rb rb₁) = x₂
-RBtreeEQ  (rb-black _ _ x rb rb₁) = x
-
-RBtreeToBlack : {n : Level} {A : Set n}
- → (tree : bt (Color ∧ A))
- → RBtreeInvariant tree
- → RBtreeInvariant (to-black tree)
-RBtreeToBlack leaf rb-leaf = rb-leaf
-RBtreeToBlack (node key ⟪ Red , value ⟫ left right) (rb-red _ _ x x₁ x₂ rb rb₁) = rb-black key value x₂ rb rb₁
-RBtreeToBlack (node key ⟪ Black , value ⟫ left right) (rb-black _ _ x rb rb₁) = rb-black key value x rb rb₁
-
-RBtreeToBlackColor : {n : Level} {A : Set n}
- → (tree : bt (Color ∧ A))
- → RBtreeInvariant tree
- → color (to-black tree) ≡ Black
-RBtreeToBlackColor leaf rb-leaf = refl
-RBtreeToBlackColor (node key ⟪ Red , value ⟫ left right) (rb-red _ _ x x₁ x₂ rb rb₁) = refl
-RBtreeToBlackColor (node key ⟪ Black , value ⟫ left right) (rb-black _ _ x rb rb₁) = refl
-
-RBtreeParentColorBlack : {n : Level} {A : Set n} → (left right  : bt (Color ∧ A)) { value : A} {key : ℕ} { c : Color}
- → RBtreeInvariant (node key ⟪ c , value ⟫ left right)
- → (color left ≡ Red) ∨ (color right ≡ Red)
- → c ≡ Black
-RBtreeParentColorBlack leaf leaf (rb-red _ _ x₁ x₂ x₃ x₄ x₅) (case1 ())
-RBtreeParentColorBlack leaf leaf (rb-red _ _ x₁ x₂ x₃ x₄ x₅) (case2 ())
-RBtreeParentColorBlack (node key ⟪ Red , proj4 ⟫ left left₁) right (rb-red _ _ () x₁ x₂ rb rb₁) (case1 x₃)
-RBtreeParentColorBlack (node key ⟪ Black , proj4 ⟫ left left₁) right (rb-red _ _ x x₁ x₂ rb rb₁) (case1 ())
-RBtreeParentColorBlack left (node key ⟪ Red , proj4 ⟫ right right₁) (rb-red _ _ x () x₂ rb rb₁) (case2 x₃)
-RBtreeParentColorBlack left (node key ⟪ Black , proj4 ⟫ right right₁) (rb-red _ _ x x₁ x₂ rb rb₁) (case2 ())
-RBtreeParentColorBlack left right (rb-black _ _ x rb rb₁) x₃ = refl
-
-RBtreeChildrenColorBlack : {n : Level} {A : Set n} → (left right  : bt (Color ∧ A)) { value : Color ∧ A} {key : ℕ}
- → RBtreeInvariant (node key value left right)
- → proj1 value  ≡ Red
- → (color left ≡ Black) ∧  (color right ≡ Black)
-RBtreeChildrenColorBlack left right (rb-red _ _ x x₁ x₂ rbi rbi₁) refl = ⟪ x , x₁ ⟫
-
---
---  findRBT exit with replaced node
---     case-eq        node value is replaced,  just do replacedTree and rebuild rb-invariant
---     case-leaf      insert new single node
---        case1       if parent node is black, just do replacedTree and rebuild rb-invariant
---        case2       if parent node is red,   increase blackdepth, do rotatation
---
-
-findRBT : {n m : Level} {A : Set n} {t : Set m} → (key : ℕ) → (tree tree0 : bt (Color ∧ A) )
-           → (stack : List (bt (Color ∧ A)))
-           → RBtreeInvariant tree ∧  stackInvariant key tree tree0 stack
-           → (next : (tree1 : bt (Color ∧ A) ) → (stack : List (bt (Color ∧ A)))
-                   → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
-                   → bt-depth tree1 < bt-depth tree → t )
-           → (exit : (tree1 : bt (Color ∧ A)) → (stack : List (bt (Color ∧ A)))
-                 → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
-                 → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )  → t ) → t
-findRBT key leaf tree0 stack rb0 next exit = exit leaf stack rb0 (case1 refl)
-findRBT key (node key₁ value left right) tree0 stack rb0 next exit with <-cmp key key₁
-findRBT key (node key₁ value left right) tree0 stack  rb0 next exit | tri< a ¬b ¬c
- = next left (left ∷ stack) ⟪ RBtreeLeftDown left right (_∧_.proj1 rb0) , s-left _ _ _ a (_∧_.proj2 rb0) ⟫  depth-1<
-findRBT key n tree0 stack  rb0 _ exit | tri≈ ¬a refl ¬c = exit n stack rb0 (case2 refl)
-findRBT key (node key₁ value left right) tree0 stack  rb0 next exit | tri> ¬a ¬b c
- = next right (right ∷ stack) ⟪ RBtreeRightDown left right (_∧_.proj1 rb0), s-right _ _ _ c (_∧_.proj2 rb0) ⟫ depth-2<
-
-
-
-findTest : {n m : Level} {A : Set n } {t : Set m }
- → (key : ℕ)
- → (tree0 : bt (Color ∧ A))
- → RBtreeInvariant tree0
- → (exit : (tree1 : bt (Color ∧ A))
-   → (stack : List (bt (Color ∧ A)))
-   → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
-   → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )  → t ) → t
-findTest {n} {m} {A} {t} k tr0 rb0 exit = TerminatingLoopS (bt (Color ∧ A) ∧ List (bt (Color ∧ A)))
- {λ p → RBtreeInvariant (proj1 p) ∧ stackInvariant k (proj1 p) tr0 (proj2 p) } (λ p → bt-depth (proj1 p)) ⟪ tr0 , tr0 ∷ [] ⟫ ⟪ rb0 , s-nil ⟫
-       $ λ p RBP loop → findRBT k (proj1 p) tr0 (proj2 p) RBP  (λ t1 s1 P2 lt1 → loop ⟪ t1 ,  s1  ⟫ P2 lt1 )
-       $ λ tr1 st P2 O → exit tr1 st P2 O
-
-
-testRBTree0 :  bt (Color ∧ ℕ)
-testRBTree0 = node 8 ⟪ Black , 800 ⟫ (node 5 ⟪ Red , 500 ⟫ (node 2 ⟪ Black , 200 ⟫ leaf leaf) (node 6 ⟪ Black , 600 ⟫ leaf leaf)) (node 10 ⟪ Red , 1000 ⟫ (leaf) (node 15 ⟪ Black , 1500 ⟫ (node 14 ⟪ Red , 1400 ⟫ leaf leaf) leaf))
-
--- testRBI0 : RBtreeInvariant testRBTree0
--- testRBI0 = rb-node-black (add< 2) (add< 1) refl (rb-node-red (add< 2) (add< 0) refl (rb-single 2 200) (rb-single 6 600)) (rb-right-red (add< 4) refl (rb-left-black (add< 0) refl (rb-single 14 1400) ))
-
--- findRBTreeTest : result
--- findRBTreeTest = findTest 14 testRBTree0 testRBI0
---        $ λ tr s P O → (record {tree = tr ; stack = s ; ti = (proj1 P) ; si = (proj2 P)})
-
--- create replaceRBTree with rotate
-
-data replacedRBTree  {n : Level} {A : Set n} (key : ℕ) (value : A)  : (before after : bt (Color ∧ A) ) → Set n where
-    -- no rotation case
-    rbr-leaf : replacedRBTree key value leaf (node key ⟪ Red , value ⟫ leaf leaf)
-    rbr-node : {value₁ : A} → {ca : Color } → {t t₁ : bt (Color ∧ A)}
-          → replacedRBTree key value (node key ⟪ ca , value₁ ⟫ t t₁) (node key ⟪ ca , value ⟫ t t₁)
-    rbr-right : {k : ℕ } {v1 : A} → {ca : Color} → {t t1 t2 : bt (Color ∧ A)}
-          → color t2 ≡ color t
-          → k < key →  replacedRBTree key value t2 t →  replacedRBTree key value (node k ⟪ ca , v1 ⟫ t1 t2) (node k ⟪ ca , v1 ⟫ t1 t)
-    rbr-left  : {k : ℕ } {v1 : A} → {ca : Color} → {t t1 t2 : bt (Color ∧ A)}
-          → color t1 ≡ color t
-          → key < k →  replacedRBTree key value t1 t →  replacedRBTree key value (node k ⟪ ca , v1 ⟫ t1 t2) (node k ⟪ ca , v1 ⟫ t t2) -- k < key → key < k
-    -- in all other case, color of replaced node is changed from Black to Red
-    -- case1 parent is black
-    rbr-black-right : {t t₁ t₂ : bt (Color ∧ A)} {value₁ : A} {key₁ : ℕ}
-         → color t₂ ≡ Red → key₁ < key  → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node key₁ ⟪ Black , value₁ ⟫ t t₁) (node key₁ ⟪ Black , value₁ ⟫ t t₂)
-    rbr-black-left : {t t₁ t₂ : bt (Color ∧ A)} {value₁ : A} {key₁ : ℕ}
-         → color t₂ ≡ Red  → key < key₁ → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node key₁ ⟪ Black , value₁ ⟫ t₁ t) (node key₁ ⟪ Black , value₁ ⟫ t₂ t)
-
-    -- case2 both parent and uncle are red (should we check uncle color?), flip color and up
-    rbr-flip-ll : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
-         → color t₂ ≡ Red → color uncle ≡ Red → key < kp  → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red   , vp ⟫ t₁ t)           uncle)
-                                    (node kg ⟪ Red ,   vg ⟫ (node kp ⟪ Black , vp ⟫ t₂ t) (to-black uncle))
-    rbr-flip-lr : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
-         → color t₂ ≡ Red → color uncle ≡ Red →  kp < key → key < kg   → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red   , vp ⟫ t t₁)           uncle)
-                                    (node kg ⟪ Red ,   vg ⟫ (node kp ⟪ Black , vp ⟫ t t₂) (to-black uncle))
-    rbr-flip-rl : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
-         → color t₂ ≡ Red → color uncle ≡ Red → kg < key → key < kp  → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle            (node kp ⟪ Red   , vp ⟫ t₁ t))
-                                    (node kg ⟪ Red ,   vg ⟫ (to-black uncle) (node kp ⟪ Black , vp ⟫ t₂ t))
-    rbr-flip-rr : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
-         → color t₂ ≡ Red → color uncle ≡ Red → kp < key   → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle            (node kp ⟪ Red   , vp ⟫ t t₁))
-                                    (node kg ⟪ Red ,   vg ⟫ (to-black uncle) (node kp ⟪ Black , vp ⟫ t t₂))
-
-    -- case6 the node is outer, rotate grand
-    rbr-rotate-ll : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
-         → color t₂ ≡ Red → key < kp  → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red , vp ⟫ t₁ t)    uncle)
-                                    (node kp ⟪ Black , vp ⟫ t₂                             (node kg ⟪ Red , vg ⟫ t uncle))
-    rbr-rotate-rr : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
-         → color t₂ ≡ Red → kp < key → replacedRBTree key value t₁ t₂
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle                          (node kp ⟪ Red   , vp ⟫ t t₁))
-                                    (node kp ⟪ Black , vp ⟫ (node kg ⟪ Red , vg ⟫ uncle t) t₂ )
-    -- case56 the node is inner, make it outer and rotate grand
-    rbr-rotate-lr : {t t₁ uncle : bt (Color ∧ A)} (t₂ t₃ : bt (Color ∧ A)) (kg kp kn : ℕ) {vg vp vn : A}
-         → color t₃ ≡ Black → kp < key → key < kg
-         → replacedRBTree key value t₁ (node kn ⟪ Red , vn ⟫ t₂ t₃)
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red , vp ⟫ t t₁)     uncle)
-                                    (node kn ⟪ Black , vn ⟫ (node kp ⟪ Red , vp ⟫ t t₂)     (node kg ⟪ Red , vg ⟫ t₃ uncle))
-    rbr-rotate-rl : {t t₁ uncle : bt (Color ∧ A)} (t₂ t₃ : bt (Color ∧ A)) (kg kp kn : ℕ) {vg vp vn : A}
-         → color t₃ ≡ Black → kg < key → key < kp
-         → replacedRBTree key value t₁ (node kn ⟪ Red , vn ⟫ t₂ t₃)
-         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle                           (node kp ⟪ Red , vp ⟫ t₁ t))
-                                    (node kn ⟪ Black , vn ⟫ (node kg ⟪ Red , vg ⟫ uncle t₂) (node kp ⟪ Red , vp ⟫ t₃ t))
-
-
---
--- Parent Grand Relation
---   should we require stack-invariant?
---
-
-data ParentGrand {n : Level} {A : Set n} (key : ℕ) (self : bt A) : (parent uncle grand : bt A) → Set n where
-    s2-s1p2 : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
-        → key < kp → parent ≡ node kp vp self n1 → grand ≡ node kg vg parent n2 → ParentGrand key self parent n2 grand
-    s2-1sp2 : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
-        → kp < key → parent ≡ node kp vp n1 self → grand ≡ node kg vg parent n2 → ParentGrand key self parent n2 grand
-    s2-s12p : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
-        → key < kp → parent ≡ node kp vp self n1 → grand ≡ node kg vg n2 parent → ParentGrand key self parent n2 grand
-    s2-1s2p : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
-        → kp < key → parent ≡ node kp vp n1 self → grand ≡ node kg vg n2 parent → ParentGrand key self parent n2 grand
-
-record PG {n : Level } (A : Set n) (key : ℕ) (self : bt A) (stack : List (bt A)) : Set n where
-    field
-       parent grand uncle : bt A
-       pg : ParentGrand key self parent uncle grand
-       rest : List (bt A)
-       stack=gp : stack ≡ ( self ∷ parent ∷ grand ∷ rest )
-
---
--- RBI : Invariant on InsertCase2
---     color repl ≡ Red ∧ black-depth repl ≡ suc (black-depth tree)
---
-
-data RBI-state  {n : Level} {A : Set n} (key : ℕ) (value : A) : (tree repl : bt (Color ∧ A) ) → (stak : List (bt (Color ∧ A))) → Set n where
-   rebuild : {tree repl : bt (Color ∧ A) } {stack : List (bt (Color ∧ A))} → color tree ≡ color repl → black-depth repl ≡ black-depth tree
-       → ¬ ( tree ≡ leaf) 
-       → (rotated : replacedRBTree key value tree repl)
-       → RBI-state key value tree repl stack  -- one stage up
-   rotate  : (tree : bt (Color ∧ A)) → {repl : bt (Color ∧ A) } {stack : List (bt (Color ∧ A))} → color repl ≡ Red 
-       → (rotated : replacedRBTree key value tree repl)
-       → RBI-state key value tree repl stack  -- two stages up
-   top-black : {tree repl : bt (Color ∧ A) } → {stack : List (bt (Color ∧ A))}  → stack ≡ tree ∷ []
-       → (rotated : replacedRBTree key value tree repl ∨ replacedRBTree key value (to-black tree) repl)
-       → RBI-state key value tree repl stack
-
-record RBI {n : Level} {A : Set n} (key : ℕ) (value : A) (orig : bt (Color ∧ A) ) (stack : List (bt (Color ∧ A)))  : Set n where
-   field
-       tree repl : bt (Color ∧ A)
-       origti : treeInvariant orig
-       origrb : RBtreeInvariant orig
-       treerb : RBtreeInvariant tree     -- tree node te be replaced
-       replrb : RBtreeInvariant repl
-       si : stackInvariant key tree orig stack
-       state : RBI-state key value tree repl stack
-
-tr>-to-black : {n : Level} {A : Set n} {key : ℕ} {tree : bt (Color ∧ A)} → tr> key tree → tr> key (to-black tree)
-tr>-to-black {n} {A} {key} {leaf} tr = tt
-tr>-to-black {n} {A} {key} {node key₁ value tree tree₁} tr = tr
-
-tr<-to-black : {n : Level} {A : Set n} {key : ℕ} {tree : bt (Color ∧ A)} → tr< key tree → tr< key (to-black tree)
-tr<-to-black {n} {A} {key} {leaf} tr = tt
-tr<-to-black {n} {A} {key} {node key₁ value tree tree₁} tr = tr
-
-to-black-eq : {n : Level} {A : Set n}  (tree : bt (Color ∧ A)) → color tree ≡ Red → suc (black-depth tree) ≡ black-depth (to-black tree)
-to-black-eq {n} {A}  (leaf) ()
-to-black-eq {n} {A}  (node key₁ ⟪ Red , proj4 ⟫ tree tree₁) eq = refl
-to-black-eq {n} {A}  (node key₁ ⟪ Black , proj4 ⟫ tree tree₁) ()
-
-red-children-eq : {n : Level} {A : Set n}  {tree left right : bt (Color ∧ A)} → {key : ℕ} → {value : A} → {c : Color}
-   → tree ≡ node key ⟪ c , value ⟫ left right
-   → c ≡ Red
-   → RBtreeInvariant tree
-   → (black-depth tree ≡ black-depth left ) ∧ (black-depth tree ≡ black-depth right)
-red-children-eq {n} {A} {.(node key₁ ⟪ Red , value₁ ⟫ left right)} {left} {right} {.key₁} {.value₁} {Red} refl eq₁ rb2@(rb-red key₁ value₁ x x₁ x₂ rb rb₁) =
-  ⟪ ( begin
-        black-depth left ⊔ black-depth right ≡⟨ cong (λ k → black-depth left ⊔ k) (sym (RBtreeEQ rb2)) ⟩
-        black-depth left ⊔ black-depth left ≡⟨ ⊔-idem _ ⟩
-        black-depth left ∎  ) ,  (
-     begin
-        black-depth left ⊔ black-depth right ≡⟨ cong (λ k → k ⊔ black-depth right ) (RBtreeEQ rb2) ⟩
-        black-depth right ⊔ black-depth right ≡⟨ ⊔-idem _ ⟩
-        black-depth right ∎ ) ⟫ where open ≡-Reasoning
-red-children-eq {n} {A} {tree} {left} {right} {key} {value} {Black} eq () rb
-
-black-children-eq : {n : Level} {A : Set n}  {tree left right : bt (Color ∧ A)} → {key : ℕ} → {value : A} → {c : Color}
-   → tree ≡ node key ⟪ c , value ⟫ left right
-   → c ≡ Black
-   → RBtreeInvariant tree
-   → (black-depth tree ≡ suc (black-depth left) ) ∧ (black-depth tree ≡ suc (black-depth right))
-black-children-eq {n} {A} {.(node key₁ ⟪ Black , value₁ ⟫ left right)} {left} {right} {.key₁} {.value₁} {Black} refl eq₁ rb2@(rb-black key₁ value₁ x rb rb₁) =
-  ⟪ ( begin
-        suc (black-depth left ⊔ black-depth right) ≡⟨ cong (λ k → suc (black-depth left ⊔ k)) (sym (RBtreeEQ rb2)) ⟩
-        suc (black-depth left ⊔ black-depth left) ≡⟨ ⊔-idem _ ⟩
-        suc (black-depth left) ∎  ) ,  (
-     begin
-        suc (black-depth left ⊔ black-depth right) ≡⟨ cong (λ k → suc (k ⊔ black-depth right)) (RBtreeEQ rb2) ⟩
-        suc (black-depth right ⊔ black-depth right) ≡⟨ ⊔-idem _ ⟩
-        suc (black-depth right) ∎ ) ⟫ where open ≡-Reasoning
-black-children-eq {n} {A} {tree} {left} {right} {key} {value} {Red} eq () rb
-
-black-depth-cong  : {n : Level} (A : Set n)  {tree tree₁ : bt (Color ∧ A)} 
-   → tree ≡ tree₁ → black-depth tree ≡ black-depth tree₁
-black-depth-cong  {n} A  {leaf} {leaf} refl = refl
-black-depth-cong {n} A {node key ⟪ Red , value ⟫ left right} {node .key ⟪ Red , .value ⟫ .left .right} refl 
-   = cong₂ (λ j k → j ⊔ k ) (black-depth-cong A {left} {left} refl) (black-depth-cong A {right} {right} refl)
-black-depth-cong {n} A {node key ⟪ Black , value ⟫ left right} {node .key ⟪ Black , .value ⟫ .left .right} refl 
-   = cong₂ (λ j k → suc (j ⊔ k) ) (black-depth-cong A {left} {left} refl) (black-depth-cong A {right} {right} refl)
-
-black-depth-resp  : {n : Level} (A : Set n)   (tree tree₁ : bt (Color ∧ A)) → {c1 c2 : Color}  { l1 l2 r1 r2 : bt (Color ∧ A)} {key1 key2 : ℕ} {value1 value2 : A} 
-   → tree ≡ node key1 ⟪ c1 , value1 ⟫ l1 r1 → tree₁ ≡ node key2 ⟪ c2 , value2 ⟫ l2 r2 
-   → color tree  ≡ color tree₁ 
-   → black-depth l1 ≡ black-depth l2 → black-depth r1 ≡ black-depth r2
-   → black-depth tree ≡ black-depth tree₁
-black-depth-resp  A _ _ {Black} {Black} refl refl refl eql eqr = cong₂ (λ j k → suc (j ⊔ k) ) eql eqr
-black-depth-resp  A _ _ {Red} {Red} refl refl refl eql eqr = cong₂ (λ j k → j ⊔ k ) eql eqr
-
-red-children-eq1 : {n : Level} {A : Set n}  {tree left right : bt (Color ∧ A)} → {key : ℕ} → {value : A} → {c : Color}
-   → tree ≡ node key ⟪ c , value ⟫ left right
-   → color tree ≡ Red
-   → RBtreeInvariant tree
-   → (black-depth tree ≡ black-depth left ) ∧ (black-depth tree ≡ black-depth right)
-red-children-eq1 {n} {A} {.(node key₁ ⟪ Red , value₁ ⟫ left right)} {left} {right} {.key₁} {.value₁} {Red} refl eq₁ rb2@(rb-red key₁ value₁ x x₁ x₂ rb rb₁) =
-  ⟪ ( begin
-        black-depth left ⊔ black-depth right ≡⟨ cong (λ k → black-depth left ⊔ k) (sym (RBtreeEQ rb2)) ⟩
-        black-depth left ⊔ black-depth left ≡⟨ ⊔-idem _ ⟩
-        black-depth left ∎  ) ,  (
-     begin
-        black-depth left ⊔ black-depth right ≡⟨ cong (λ k → k ⊔ black-depth right ) (RBtreeEQ rb2) ⟩
-        black-depth right ⊔ black-depth right ≡⟨ ⊔-idem _ ⟩
-        black-depth right ∎ ) ⟫ where open ≡-Reasoning
-red-children-eq1 {n} {A} {.(node key ⟪ Black , value ⟫ left right)} {left} {right} {key} {value} {Black} refl () rb
-
-black-children-eq1 : {n : Level} {A : Set n}  {tree left right : bt (Color ∧ A)} → {key : ℕ} → {value : A} → {c : Color}
-   → tree ≡ node key ⟪ c , value ⟫ left right
-   → color tree ≡ Black
-   → RBtreeInvariant tree
-   → (black-depth tree ≡ suc (black-depth left) ) ∧ (black-depth tree ≡ suc (black-depth right))
-black-children-eq1 {n} {A} {.(node key₁ ⟪ Black , value₁ ⟫ left right)} {left} {right} {.key₁} {.value₁} {Black} refl eq₁ rb2@(rb-black key₁ value₁ x rb rb₁) =
-  ⟪ ( begin
-        suc (black-depth left ⊔ black-depth right) ≡⟨ cong (λ k → suc (black-depth left ⊔ k)) (sym (RBtreeEQ rb2)) ⟩
-        suc (black-depth left ⊔ black-depth left) ≡⟨ ⊔-idem _ ⟩
-        suc (black-depth left) ∎  ) ,  (
-     begin
-        suc (black-depth left ⊔ black-depth right) ≡⟨ cong (λ k → suc (k ⊔ black-depth right)) (RBtreeEQ rb2) ⟩
-        suc (black-depth right ⊔ black-depth right) ≡⟨ ⊔-idem _ ⟩
-        suc (black-depth right) ∎ ) ⟫ where open ≡-Reasoning
-black-children-eq1 {n} {A} {.(node key ⟪ Red , value ⟫ left right)} {left} {right} {key} {value} {Red} refl () rb
-
-
-rbi-from-red-black : {n : Level } {A : Set n} → (n1 rp-left : bt (Color ∧ A)) → (kp : ℕ) → (vp : Color ∧ A) 
-    → RBtreeInvariant n1 → RBtreeInvariant rp-left
-    → black-depth n1 ≡ black-depth rp-left
-    → color n1 ≡ Black → color rp-left ≡ Black →  ⟪ Red , proj2 vp ⟫ ≡ vp
-    → RBtreeInvariant (node kp vp n1 rp-left)
-rbi-from-red-black leaf leaf kp vp rb1 rbp deq ceq1 ceq2 ceq3 
-    = subst (λ k → RBtreeInvariant (node kp k leaf leaf)) ceq3 (rb-red kp (proj2 vp)  refl refl refl rb-leaf rb-leaf)
-rbi-from-red-black leaf (node key ⟪ .Black , proj3 ⟫ trpl trpl₁) kp vp rb1 rbp deq ceq1 refl ceq3 
-    = subst (λ k → RBtreeInvariant (node kp k _ _)) ceq3 (rb-red kp (proj2 vp) refl refl deq rb1 rbp)
-rbi-from-red-black (node key ⟪ .Black , proj3 ⟫ tn1 tn2) leaf kp vp rb1 rbp deq refl ceq2 ceq3 
-    = subst (λ k → RBtreeInvariant (node kp k _ _)) ceq3 (rb-red kp (proj2 vp) refl refl deq rb1 rbp)
-rbi-from-red-black (node key ⟪ .Black , proj3 ⟫ tn1 tn2) (node key₁ ⟪ .Black , proj4 ⟫ trpl trpl₁) kp vp rb1 rbp deq refl refl ceq3 
-  = subst (λ k → RBtreeInvariant (node kp k _ _)) ceq3 (rb-red kp (proj2 vp) refl refl deq rb1 rbp )
-
-⊔-succ : {m n : ℕ} → suc (m ⊔ n) ≡ suc m ⊔ suc n
-⊔-succ {m} {n} = refl
-
-RB-repl-node  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → {key : ℕ} → {value : A}
-     → replacedRBTree key value tree repl → ¬ ( repl ≡ leaf)
-RB-repl-node {n} {A} .leaf .(node _ ⟪ Red , _ ⟫ leaf leaf) rbr-leaf ()
-RB-repl-node {n} {A} .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) rbr-node ()
-RB-repl-node {n} {A} .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) (rbr-right x x₁ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) (rbr-left x x₁ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) (rbr-black-right x x₁ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) (rbr-black-left x x₁ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) (rbr-flip-ll x x₁ x₂ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) (rbr-flip-lr x x₁ x₂ x₃ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) (rbr-flip-rl x x₁ x₂ x₃ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) (rbr-flip-rr x x₁ x₂ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) (rbr-rotate-ll x x₁ rpl) ()
-RB-repl-node {n} {A} .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) (rbr-rotate-rr x x₁ rpl) ()
-RB-repl-node {n} {A} .(node kg ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ _) _) .(node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ t₂) (node kg ⟪ Red , _ ⟫ t₃ _)) (rbr-rotate-lr t₂ t₃ kg kp kn x x₁ x₂ rpl) ()
-RB-repl-node {n} {A} .(node kg ⟪ Black , _ ⟫ _ (node kp ⟪ Red , _ ⟫ _ _)) .(node kn ⟪ Black , _ ⟫ (node kg ⟪ Red , _ ⟫ _ t₂) (node kp ⟪ Red , _ ⟫ t₃ _)) (rbr-rotate-rl t₂ t₃ kg kp kn x x₁ x₂ rpl) ()
-
-RB-repl→eq  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → {key : ℕ} → {value : A}
-     → RBtreeInvariant tree
-     → replacedRBTree key value tree repl → black-depth tree ≡ black-depth repl
-RB-repl→eq {n} {A} .leaf .(node _ ⟪ Red , _ ⟫ leaf leaf) rbt rbr-leaf = refl
-RB-repl→eq {n} {A} (node _ ⟪ Red , _ ⟫ _ _) .(node _ ⟪ Red , _ ⟫ _ _) rbt rbr-node = refl
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) rbt rbr-node = refl
-RB-repl→eq {n} {A} (node _ ⟪ Red , _ ⟫ left _) .(node _ ⟪ Red , _ ⟫ left _) (rb-red _ _ x₂ x₃ x₄ rbt rbt₁) (rbr-right x x₁ t) =
-   cong (λ k → black-depth left ⊔ k ) (RB-repl→eq _ _ rbt₁ t)
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ left _) .(node _ ⟪ Black , _ ⟫ left _) (rb-black _ _ x₂ rbt rbt₁) (rbr-right x x₁ t) =
-   cong (λ k → suc (black-depth left ⊔ k)) (RB-repl→eq _ _ rbt₁ t)
-RB-repl→eq {n} {A} (node _ ⟪ Red , _ ⟫ _ right) .(node _ ⟪ Red , _ ⟫ _ right) (rb-red _ _ x₂ x₃ x₄ rbt rbt₁) (rbr-left x x₁ t) = cong (λ k → k ⊔ black-depth right) (RB-repl→eq _ _ rbt t)
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ _ right) .(node _ ⟪ Black , _ ⟫ _ right) (rb-black _ _ x₂ rbt rbt₁) (rbr-left x x₁ t) = cong (λ k → suc (k ⊔ black-depth right)) (RB-repl→eq _ _ rbt t)
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ t₁ _) .(node _ ⟪ Black , _ ⟫ t₁ _) (rb-black _ _ x₂ rbt rbt₁) (rbr-black-right x x₁ t) = cong (λ k → suc (black-depth t₁ ⊔ k)) (RB-repl→eq _ _ rbt₁ t)
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ _ t₁) .(node _ ⟪ Black , _ ⟫ _ t₁) (rb-black _ _ x₂ rbt rbt₁) (rbr-black-left x x₁ t) = cong (λ k → suc (k ⊔ black-depth t₁)) (RB-repl→eq _ _ rbt t)
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ t₁ t₂) t₃) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ t₄ t₂) (to-black t₃)) (rb-black _ _ x₃ (rb-red _ _ x₄ x₅ x₆ rbt rbt₂) rbt₁) (rbr-flip-ll {_} {_} {t₄} x x₁ x₂ t) = begin
-   suc (black-depth t₁ ⊔ black-depth t₂ ⊔ black-depth t₃)  ≡⟨ cong (λ k → suc (k ⊔ black-depth t₂ ⊔ black-depth t₃)) (RB-repl→eq _ _ rbt t) ⟩
-   suc (black-depth t₄ ⊔ black-depth t₂) ⊔ suc (black-depth t₃)  ≡⟨ cong (λ k → suc (black-depth t₄ ⊔ black-depth t₂) ⊔ k )  (  to-black-eq t₃ x₁ ) ⟩
-   suc (black-depth t₄ ⊔ black-depth t₂) ⊔ black-depth (to-black t₃) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ t₁ t₂) t₃) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ t₁ t₄) (to-black t₃)) (rb-black _ _ x₄ (rb-red _ _ x₅ x₆ x₇ rbt rbt₂) rbt₁) (rbr-flip-lr {_} {_} {t₄} x x₁ x₂ x₃ t) = begin
-   suc (black-depth t₁ ⊔ black-depth t₂) ⊔ suc (black-depth t₃)  ≡⟨ cong (λ k → suc (black-depth t₁ ⊔ black-depth t₂) ⊔ k )  (  to-black-eq t₃ x₁ ) ⟩
-   suc (black-depth t₁ ⊔ black-depth t₂) ⊔ black-depth (to-black t₃) ≡⟨ cong (λ k → suc (black-depth t₁ ⊔ k ) ⊔ black-depth (to-black t₃)) (RB-repl→eq _ _ rbt₂ t) ⟩
-   suc (black-depth t₁ ⊔ black-depth t₄) ⊔ black-depth (to-black t₃) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} (node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black t₄) (node _ ⟪ Black , _ ⟫ t₃ t₁)) (rb-black _ _ x₄ rbt (rb-red _ _ x₅ x₆ x₇ rbt₁ rbt₂)) (rbr-flip-rl {t₁} {t₂} {t₃} {t₄} x x₁ x₂ x₃ t) = begin
-   suc (black-depth t₄ ⊔ (black-depth t₂ ⊔ black-depth t₁)) ≡⟨ cong (λ k → suc (black-depth t₄ ⊔ ( k  ⊔ black-depth t₁)) ) (RB-repl→eq _ _ rbt₁ t) ⟩
-   suc (black-depth t₄ ⊔ (black-depth t₃ ⊔ black-depth t₁)) ≡⟨ cong (λ k → k ⊔ suc (black-depth t₃ ⊔ black-depth t₁)) ( to-black-eq t₄ x₁ ) ⟩
-   black-depth (to-black t₄) ⊔ suc (black-depth t₃ ⊔ black-depth t₁) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) (rb-black _ _ x₃ rbt (rb-red _ _ x₄ x₅ x₆ rbt₁ rbt₂)) (rbr-flip-rr {t₁} {t₂} {t₃} {t₄} x x₁ x₂ t) = begin
-   suc (black-depth t₄ ⊔ (black-depth t₁ ⊔ black-depth t₂)) ≡⟨ cong (λ k → suc (black-depth t₄ ⊔ (black-depth t₁ ⊔ k ))) ( RB-repl→eq _ _ rbt₂ t) ⟩
-   suc (black-depth t₄ ⊔ (black-depth t₁ ⊔ black-depth t₃)) ≡⟨ cong (λ k → k ⊔ suc (black-depth t₁ ⊔ black-depth t₃)) ( to-black-eq t₄ x₁ ) ⟩
-   black-depth (to-black t₄) ⊔ suc (black-depth t₁ ⊔ black-depth t₃) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) (rb-black _ _ x₂ (rb-red _ _ x₃ x₄ x₅ rbt rbt₂) rbt₁) (rbr-rotate-ll {t₁} {t₂} {t₃} {t₄} x x₁ t) = begin
-   suc (black-depth t₂ ⊔ black-depth t₁ ⊔ black-depth t₄) ≡⟨ cong suc ( ⊔-assoc (black-depth t₂) (black-depth t₁) (black-depth t₄)) ⟩
-   suc (black-depth t₂ ⊔ (black-depth t₁ ⊔ black-depth t₄)) ≡⟨ cong (λ k → suc (k ⊔ (black-depth t₁ ⊔ black-depth t₄)) ) (RB-repl→eq _ _ rbt t) ⟩
-   suc (black-depth t₃ ⊔ (black-depth t₁ ⊔ black-depth t₄)) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) (rb-black _ _ x₂ rbt (rb-red _ _ x₃ x₄ x₅ rbt₁ rbt₂)) (rbr-rotate-rr {t₁} {t₂} {t₃} {t₄} x x₁ t) = begin
-   suc (black-depth t₄ ⊔ (black-depth t₁ ⊔ black-depth t₂)) ≡⟨ cong (λ k → suc (black-depth t₄ ⊔ (black-depth t₁ ⊔ k ))) ( RB-repl→eq _ _ rbt₂ t) ⟩
-   suc (black-depth t₄ ⊔ (black-depth t₁ ⊔ black-depth t₃)) ≡⟨ cong suc  (sym ( ⊔-assoc (black-depth t₄) (black-depth t₁) (black-depth t₃))) ⟩
-   suc (black-depth t₄ ⊔ black-depth t₁ ⊔ black-depth t₃) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} .(node kg ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ _) _) .(node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ t₂) (node kg ⟪ Red , _ ⟫ t₃ _)) (rb-black .kg _ x₃ (rb-red .kp _ x₄ x₅ x₆ rbt rbt₂) rbt₁) (rbr-rotate-lr {t₀} {t₁} {uncle} t₂ t₃ kg kp kn x x₁ x₂ t) = begin
-   suc (black-depth t₀ ⊔ black-depth t₁ ⊔ black-depth uncle) ≡⟨ cong suc ( ⊔-assoc (black-depth t₀) (black-depth t₁) (black-depth uncle)) ⟩
-   suc (black-depth t₀ ⊔ (black-depth t₁ ⊔ black-depth uncle)) ≡⟨ cong (λ k → suc (black-depth t₀ ⊔ (k ⊔ black-depth uncle))) (RB-repl→eq _ _ rbt₂ t) ⟩
-   suc (black-depth t₀ ⊔ ((black-depth t₂ ⊔ black-depth t₃) ⊔ black-depth uncle)) ≡⟨ cong (λ k → suc (black-depth t₀ ⊔ k )) ( ⊔-assoc (black-depth t₂) (black-depth t₃) (black-depth uncle)) ⟩
-   suc (black-depth t₀ ⊔ (black-depth t₂ ⊔ (black-depth t₃ ⊔ black-depth uncle)))  ≡⟨ cong suc (sym ( ⊔-assoc (black-depth t₀) (black-depth t₂) (black-depth t₃ ⊔ black-depth uncle))) ⟩
-   suc (black-depth t₀ ⊔ black-depth t₂ ⊔ (black-depth t₃ ⊔ black-depth uncle)) ∎
-     where open ≡-Reasoning
-RB-repl→eq {n} {A} .(node kg ⟪ Black , _ ⟫ _ (node kp ⟪ Red , _ ⟫ _ _)) .(node kn ⟪ Black , _ ⟫ (node kg ⟪ Red , _ ⟫ _ t₂) (node kp ⟪ Red , _ ⟫ t₃ _)) (rb-black .kg _ x₃ rbt (rb-red .kp _ x₄ x₅ x₆ rbt₁ rbt₂)) (rbr-rotate-rl {t₀} {t₁} {uncle} t₂ t₃ kg kp kn x x₁ x₂ t) = begin
-   suc (black-depth uncle ⊔ (black-depth t₁ ⊔ black-depth t₀)) ≡⟨ cong (λ k → suc (black-depth uncle ⊔ (k ⊔ black-depth t₀))) (RB-repl→eq _ _ rbt₁ t) ⟩
-   suc (black-depth uncle ⊔ ((black-depth t₂ ⊔ black-depth t₃)  ⊔ black-depth t₀)) ≡⟨ cong (λ k → suc (black-depth uncle ⊔ k)) ( ⊔-assoc (black-depth t₂) (black-depth t₃) (black-depth t₀)) ⟩
-   suc (black-depth uncle ⊔ (black-depth t₂ ⊔ (black-depth t₃ ⊔ black-depth t₀))) ≡⟨ cong suc (sym ( ⊔-assoc (black-depth uncle) (black-depth t₂) (black-depth t₃ ⊔ black-depth t₀))) ⟩
-   suc (black-depth uncle ⊔ black-depth t₂ ⊔ (black-depth t₃ ⊔ black-depth t₀)) ∎
-     where open ≡-Reasoning
-
-
-RB-repl→ti>  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → (key key₁ : ℕ) → (value : A)
-     → replacedRBTree key value tree repl → key₁ < key → tr> key₁ tree → tr> key₁ repl
-RB-repl→ti> .leaf .(node key ⟪ Red , value ⟫ leaf leaf) key key₁ value rbr-leaf lt tr = ⟪ lt , ⟪ tt , tt ⟫ ⟫
-RB-repl→ti> .(node key ⟪ _ , _ ⟫ _ _) .(node key ⟪ _ , value ⟫ _ _) key key₁ value (rbr-node ) lt tr = tr
-RB-repl→ti> .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-right _ x rbt) lt tr
-   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti> _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-left _ x rbt) lt tr
-   = ⟪ proj1 tr , ⟪ RB-repl→ti> _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-right x _ rbt) lt tr
-   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti> _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-left x _ rbt) lt tr
-   = ⟪ proj1 tr , ⟪ RB-repl→ti> _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value (rbr-flip-ll x _ _ rbt) lt tr
-   = ⟪ proj1 tr , ⟪ ⟪ proj1 (proj1 (proj2 tr))  , ⟪ RB-repl→ti> _ _ _ _ _ rbt lt (proj1 (proj2 (proj1 (proj2 tr))))
-       , proj2 (proj2 (proj1 (proj2 tr))) ⟫ ⟫  , tr>-to-black (proj2 (proj2 tr)) ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value
-   (rbr-flip-lr x _ _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5 ⟫ ⟫ = ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti> _ _ _ _ _ rbt lt tr7 ⟫ ⟫  , tr>-to-black tr5 ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
-   (rbr-flip-rl x _ _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫ = ⟪ tr3 , ⟪ tr>-to-black tr5 , ⟪ tr4 , ⟪  RB-repl→ti> _ _ _ _ _ rbt lt tr6 , tr7 ⟫ ⟫   ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
-   (rbr-flip-rr x _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ ⟫ ⟫ = ⟪ tr3 , ⟪ tr>-to-black tr5 , ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti> _ _ _ _ _ rbt lt tr7 ⟫ ⟫   ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
-   (rbr-rotate-ll x lt2 rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ tr4 , ⟪  RB-repl→ti> _ _ _ _ _ rbt lt tr6 , ⟪ tr3 , ⟪ tr7 , tr5 ⟫ ⟫ ⟫ ⟫
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) key key₁ value
-   (rbr-rotate-rr x lt2 rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ tr4 , ⟪ ⟪ tr3 , ⟪ tr5 , tr6 ⟫ ⟫ , RB-repl→ti> _ _ _ _ _ rbt lt tr7 ⟫ ⟫
-RB-repl→ti> (node kg ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ _) _) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
-   (rbr-rotate-lr left right _ _ kn _ _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ rr00 , ⟪ ⟪ tr4 , ⟪ tr6 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr3 , ⟪ proj2 (proj2 rr01) , tr5 ⟫ ⟫ ⟫ ⟫ where
-       rr01 : (key₁ < kn) ∧ tr> key₁ left  ∧ tr> key₁ right
-       rr01 = RB-repl→ti> _ _ _ _ _ rbt lt tr7
-       rr00 : key₁ < kn
-       rr00 = proj1 rr01
-RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
-   (rbr-rotate-rl left right kg kp kn _ _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ rr00 , ⟪  ⟪ tr3 , ⟪ tr5 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr4 , ⟪ proj2 (proj2 rr01) , tr7 ⟫ ⟫ ⟫ ⟫ where
-       rr01 : (key₁ < kn) ∧ tr> key₁ left  ∧ tr> key₁ right
-       rr01 = RB-repl→ti> _ _ _ _ _ rbt lt tr6
-       rr00 : key₁ < kn
-       rr00 = proj1 rr01
-
-RB-repl→ti<  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → (key key₁ : ℕ) → (value : A)
-     → replacedRBTree key value tree repl → key < key₁ → tr< key₁ tree → tr< key₁ repl
-RB-repl→ti< .leaf .(node key ⟪ Red , value ⟫ leaf leaf) key key₁ value rbr-leaf lt tr = ⟪ lt , ⟪ tt , tt ⟫ ⟫
-RB-repl→ti< .(node key ⟪ _ , _ ⟫ _ _) .(node key ⟪ _ , value ⟫ _ _) key key₁ value (rbr-node ) lt tr = tr
-RB-repl→ti< .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-right _ x rbt) lt tr
-   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti< _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-left _ x rbt) lt tr
-   = ⟪ proj1 tr , ⟪ RB-repl→ti< _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-right x _ rbt) lt tr
-   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti< _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-left x _ rbt) lt tr
-   = ⟪ proj1 tr , ⟪ RB-repl→ti< _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value (rbr-flip-ll x _ _ rbt) lt tr
-   = ⟪ proj1 tr , ⟪ ⟪ proj1 (proj1 (proj2 tr))  , ⟪ RB-repl→ti< _ _ _ _ _ rbt lt (proj1 (proj2 (proj1 (proj2 tr))))
-       , proj2 (proj2 (proj1 (proj2 tr))) ⟫ ⟫  , tr<-to-black (proj2 (proj2 tr)) ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value
-   (rbr-flip-lr x _ _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5 ⟫ ⟫ = ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti< _ _ _ _ _ rbt lt tr7 ⟫ ⟫  , tr<-to-black tr5 ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
-   (rbr-flip-rl x _ _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫ = ⟪ tr3 , ⟪ tr<-to-black tr5 , ⟪ tr4 , ⟪  RB-repl→ti< _ _ _ _ _ rbt lt tr6 , tr7 ⟫ ⟫   ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
-   (rbr-flip-rr x _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ ⟫ ⟫ = ⟪ tr3 , ⟪ tr<-to-black tr5 , ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti< _ _ _ _ _ rbt lt tr7 ⟫ ⟫   ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
-   (rbr-rotate-ll x lt2 rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ tr4 , ⟪  RB-repl→ti< _ _ _ _ _ rbt lt tr6 , ⟪ tr3 , ⟪ tr7 , tr5 ⟫ ⟫ ⟫ ⟫
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) key key₁ value
-   (rbr-rotate-rr x lt2 rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ tr4 , ⟪ ⟪ tr3 , ⟪ tr5 , tr6 ⟫ ⟫ , RB-repl→ti< _ _ _ _ _ rbt lt tr7 ⟫ ⟫
-RB-repl→ti< (node kg ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ _) _) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
-   (rbr-rotate-lr left right _ _ kn _ _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ rr00 , ⟪ ⟪ tr4 , ⟪ tr6 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr3 , ⟪ proj2 (proj2 rr01) , tr5 ⟫ ⟫ ⟫ ⟫ where
-       rr01 : (kn < key₁ ) ∧ tr< key₁ left  ∧ tr< key₁ right
-       rr01 = RB-repl→ti< _ _ _ _ _ rbt lt tr7
-       rr00 : kn < key₁
-       rr00 = proj1 rr01
-RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
-   (rbr-rotate-rl left right kg kp kn _ _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ rr00 , ⟪  ⟪ tr3 , ⟪ tr5 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr4 , ⟪ proj2 (proj2 rr01) , tr7 ⟫ ⟫ ⟫ ⟫ where
-       rr01 : (kn < key₁ ) ∧ tr< key₁ left  ∧ tr< key₁ right
-       rr01 = RB-repl→ti< _ _ _ _ _ rbt lt tr6
-       rr00 : kn < key₁
-       rr00 = proj1 rr01
-
-RB-repl→ti : {n : Level} {A : Set n} → (tree repl : bt (Color ∧ A) ) → (key : ℕ ) → (value : A) → treeInvariant tree
-       → replacedRBTree key value tree repl → treeInvariant repl
-RB-repl→ti = ?
-
-
---
--- if we consider tree invariant, this may be much simpler and faster
---
-stackToPG : {n : Level} {A : Set n} → {key : ℕ } → (tree orig : bt A )
-           →  (stack : List (bt A)) → stackInvariant key tree orig stack
-           → ( stack ≡ orig ∷ [] ) ∨ ( stack ≡ tree ∷ orig ∷ [] ) ∨ PG A key tree stack
-stackToPG {n} {A} {key} tree .tree .(tree ∷ []) s-nil = case1 refl
-stackToPG {n} {A} {key} tree .(node _ _ _ tree) .(tree ∷ node _ _ _ tree ∷ []) (s-right _ _ _ x s-nil) = case2 (case1 refl)
-stackToPG {n} {A} {key} tree .(node k2 v2 t5 (node k1 v1 t2 tree)) (tree ∷ node _ _ _ tree ∷ .(node k2 v2 t5 (node k1 v1 t2 tree) ∷ [])) (s-right tree (node k2 v2 t5 (node k1 v1 t2 tree)) t2 {k1} {v1} x (s-right (node k1 v1 t2 tree) (node k2 v2 t5 (node k1 v1 t2 tree)) t5 {k2} {v2} x₁ s-nil)) = case2 (case2
-    record {  parent = node k1 v1 t2 tree ;  grand = _ ; pg = s2-1s2p  x refl refl  ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig (tree ∷ node _ _ _ tree ∷ .(node k2 v2 t5 (node k1 v1 t2 tree) ∷ _)) (s-right tree orig t2 {k1} {v1} x (s-right (node k1 v1 t2 tree) orig t5 {k2} {v2} x₁ (s-right _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 t2 tree ;  grand = _ ; pg = s2-1s2p  x  refl refl  ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig (tree ∷ node _ _ _ tree ∷ .(node k2 v2 t5 (node k1 v1 t2 tree) ∷ _)) (s-right tree orig t2 {k1} {v1} x (s-right (node k1 v1 t2 tree) orig t5 {k2} {v2} x₁ (s-left _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 t2 tree ;  grand = _ ; pg = s2-1s2p  x refl refl  ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree .(node k2 v2 (node k1 v1 t1 tree) t2) .(tree ∷ node k1 v1 t1 tree ∷ node k2 v2 (node k1 v1 t1 tree) t2 ∷ []) (s-right _ _ t1 {k1} {v1} x (s-left _ _ t2 {k2} {v2} x₁ s-nil)) = case2 (case2
-    record {  parent = node k1 v1 t1 tree ;  grand = _ ; pg = s2-1sp2 x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 t1 tree ∷ node k2 v2 (node k1 v1 t1 tree) t2 ∷ _) (s-right _ _ t1 {k1} {v1} x (s-left _ _ t2 {k2} {v2} x₁ (s-right _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 t1 tree ;  grand = _ ; pg = s2-1sp2 x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 t1 tree ∷ node k2 v2 (node k1 v1 t1 tree) t2 ∷ _) (s-right _ _ t1 {k1} {v1} x (s-left _ _ t2 {k2} {v2} x₁ (s-left _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 t1 tree ;  grand = _ ; pg = s2-1sp2 x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree .(node _ _ tree _) .(tree ∷ node _ _ tree _ ∷ []) (s-left _ _ t1 {k1} {v1} x s-nil) = case2 (case1 refl)
-stackToPG {n} {A} {key} tree .(node _ _ _ (node k1 v1 tree t1)) .(tree ∷ node k1 v1 tree t1 ∷ node _ _ _ (node k1 v1 tree t1) ∷ []) (s-left _ _ t1 {k1} {v1} x (s-right _ _ _ x₁ s-nil)) = case2 (case2
-    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s12p x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ _ (node k1 v1 tree t1) ∷ _) (s-left _ _ t1 {k1} {v1} x (s-right _ _ _ x₁ (s-right _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s12p x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ _ (node k1 v1 tree t1) ∷ _) (s-left _ _ t1 {k1} {v1} x (s-right _ _ _ x₁ (s-left _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s12p x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree .(node _ _ (node k1 v1 tree t1) _) .(tree ∷ node k1 v1 tree t1 ∷ node _ _ (node k1 v1 tree t1) _ ∷ []) (s-left _ _ t1 {k1} {v1} x (s-left _ _ _ x₁ s-nil)) = case2 (case2
-    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s1p2 x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ (node k1 v1 tree t1) _ ∷ _) (s-left _ _ t1 {k1} {v1} x (s-left _ _ _ x₁ (s-right _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s1p2 x refl refl ; rest = _ ; stack=gp = refl } )
-stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ (node k1 v1 tree t1) _ ∷ _) (s-left _ _ t1 {k1} {v1} x (s-left _ _ _ x₁ (s-left _ _ _ x₂ si))) = case2 (case2
-    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s1p2 x refl refl ; rest = _ ; stack=gp = refl } )
-
-stackCase1 : {n : Level} {A : Set n} → {key : ℕ } → {tree orig : bt A }
-           →  {stack : List (bt A)} → stackInvariant key tree orig stack
-           →  stack ≡ orig ∷ [] → tree ≡ orig
-stackCase1 s-nil refl = refl
-
-pg-prop-1 : {n : Level} (A : Set n) → (key : ℕ) → (tree orig : bt A )
-           →  (stack : List (bt A)) → (pg : PG A key tree stack)
-           → (¬  PG.grand pg ≡ leaf ) ∧  (¬  PG.parent pg ≡ leaf)
-pg-prop-1 {_} A _ tree orig stack pg with PG.pg pg
-... | s2-s1p2 _ refl refl = ⟪ (λ () ) , ( λ () ) ⟫
-... | s2-1sp2 _ refl refl = ⟪ (λ () ) , ( λ () ) ⟫
-... | s2-s12p _ refl refl = ⟪ (λ () ) , ( λ () ) ⟫
-... | s2-1s2p _ refl refl = ⟪ (λ () ) , ( λ () ) ⟫
-
-popStackInvariant : {n : Level} {A : Set n} → (rest : List ( bt (Color ∧ A)))
-           → ( tree parent orig : bt (Color ∧ A)) →  (key : ℕ)
-           → stackInvariant key tree  orig ( tree ∷ parent ∷ rest )
-           → stackInvariant key parent orig (parent ∷ rest )
-popStackInvariant rest tree parent orig key (s-right .tree .orig tree₁ x si) = sc00 where
-     sc00 : stackInvariant key parent orig (parent ∷ rest )
-     sc00 with si-property1 si
-     ... | refl = si
-popStackInvariant rest tree parent orig key (s-left .tree .orig tree₁ x si) = sc00 where
-     sc00 : stackInvariant key parent orig (parent ∷ rest )
-     sc00 with si-property1 si
-     ... | refl = si
-
-
-siToTreeinvariant : {n : Level} {A : Set n} → (rest : List ( bt (Color ∧ A)))
-           → ( tree orig : bt (Color ∧ A)) →  (key : ℕ)
-           → treeInvariant orig
-           → stackInvariant key tree  orig ( tree ∷ rest )
-           → treeInvariant tree
-siToTreeinvariant .[] tree .tree key ti s-nil = ti
-siToTreeinvariant .(node _ _ leaf leaf ∷ []) .leaf .(node _ _ leaf leaf) key (t-single _ _) (s-right .leaf .(node _ _ leaf leaf) .leaf x s-nil) = t-leaf
-siToTreeinvariant .(node _ _ leaf (node key₁ _ _ _) ∷ []) .(node key₁ _ _ _) .(node _ _ leaf (node key₁ _ _ _)) key (t-right _ key₁ x₁ x₂ x₃ ti) (s-right .(node key₁ _ _ _) .(node _ _ leaf (node key₁ _ _ _)) .leaf x s-nil) = ti
-siToTreeinvariant .(node _ _ (node key₁ _ _ _) leaf ∷ []) .leaf .(node _ _ (node key₁ _ _ _) leaf) key (t-left key₁ _ x₁ x₂ x₃ ti) (s-right .leaf .(node _ _ (node key₁ _ _ _) leaf) .(node key₁ _ _ _) x s-nil) = t-leaf
-siToTreeinvariant .(node _ _ (node key₁ _ _ _) (node key₂ _ _ _) ∷ []) .(node key₂ _ _ _) .(node _ _ (node key₁ _ _ _) (node key₂ _ _ _)) key (t-node key₁ _ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (s-right .(node key₂ _ _ _) .(node _ _ (node key₁ _ _ _) (node key₂ _ _ _)) .(node key₁ _ _ _) x s-nil) = ti₁
-siToTreeinvariant .(node _ _ tree₁ tree ∷ _) tree orig key ti (s-right .tree .orig tree₁ x si2@(s-right .(node _ _ tree₁ tree) .orig tree₂ x₁ si)) with siToTreeinvariant _ _ _ _ ti si2
-... | t-single _ _ = t-leaf
-... | t-right _ key₁ x₂ x₃ x₄ ti₁ = ti₁
-... | t-left key₁ _ x₂ x₃ x₄ ti₁ = t-leaf
-... | t-node key₁ _ key₂ x₂ x₃ x₄ x₅ x₆ x₇ ti₁ ti₂ = ti₂
-siToTreeinvariant .(node _ _ tree₁ tree ∷ _) tree orig key ti (s-right .tree .orig tree₁ x si2@(s-left .(node _ _ tree₁ tree) .orig tree₂ x₁ si)) with siToTreeinvariant _ _ _ _ ti si2
-... | t-single _ _ = t-leaf
-... | t-right _ key₁ x₂ x₃ x₄ ti₁ = ti₁
-... | t-left key₁ _ x₂ x₃ x₄ ti₁ = t-leaf
-... | t-node key₁ _ key₂ x₂ x₃ x₄ x₅ x₆ x₇ ti₁ ti₂ = ti₂
-siToTreeinvariant .(node _ _ leaf leaf ∷ []) .leaf .(node _ _ leaf leaf) key (t-single _ _) (s-left .leaf .(node _ _ leaf leaf) .leaf x s-nil) = t-leaf
-siToTreeinvariant .(node _ _ leaf (node key₁ _ _ _) ∷ []) .leaf .(node _ _ leaf (node key₁ _ _ _)) key (t-right _ key₁ x₁ x₂ x₃ ti) (s-left .leaf .(node _ _ leaf (node key₁ _ _ _)) .(node key₁ _ _ _) x s-nil) = t-leaf
-siToTreeinvariant .(node _ _ (node key₁ _ _ _) leaf ∷ []) .(node key₁ _ _ _) .(node _ _ (node key₁ _ _ _) leaf) key (t-left key₁ _ x₁ x₂ x₃ ti) (s-left .(node key₁ _ _ _) .(node _ _ (node key₁ _ _ _) leaf) .leaf x s-nil) = ti
-siToTreeinvariant .(node _ _ (node key₁ _ _ _) (node key₂ _ _ _) ∷ []) .(node key₁ _ _ _) .(node _ _ (node key₁ _ _ _) (node key₂ _ _ _)) key (t-node key₁ _ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (s-left .(node key₁ _ _ _) .(node _ _ (node key₁ _ _ _) (node key₂ _ _ _)) .(node key₂ _ _ _) x s-nil) = ti
-siToTreeinvariant .(node _ _ tree tree₁ ∷ _) tree orig key ti (s-left .tree .orig tree₁ x si2@(s-right .(node _ _ tree tree₁) .orig tree₂ x₁ si)) with siToTreeinvariant _ _ _ _ ti si2
-... | t-single _ _ = t-leaf
-... | t-right _ key₁ x₂ x₃ x₄ t = t-leaf
-... | t-left key₁ _ x₂ x₃ x₄ t = t
-... | t-node key₁ _ key₂ x₂ x₃ x₄ x₅ x₆ x₇ t t₁ = t
-siToTreeinvariant .(node _ _ tree tree₁ ∷ _) tree orig key ti (s-left .tree .orig tree₁ x si2@(s-left .(node _ _ tree tree₁) .orig tree₂ x₁ si)) with siToTreeinvariant _ _ _ _ ti si2
-... | t-single _ _ = t-leaf
-... | t-right _ key₁ x₂ x₃ x₄ t = t-leaf
-... | t-left key₁ _ x₂ x₃ x₄ t = t
-... | t-node key₁ _ key₂ x₂ x₃ x₄ x₅ x₆ x₇ t t₁ = t
-
-PGtoRBinvariant1 : {n : Level} {A : Set n}
-           → (tree orig : bt (Color ∧ A) )
-           → {key : ℕ }
-           →  (rb : RBtreeInvariant orig)
-           →  (stack : List (bt (Color ∧ A)))  → (si : stackInvariant key tree orig stack )
-           →  RBtreeInvariant tree
-PGtoRBinvariant1 tree .tree rb .(tree ∷ []) s-nil = rb
-PGtoRBinvariant1 tree orig rb (tree ∷ rest) (s-right .tree .orig tree₁ x si) with PGtoRBinvariant1 _ orig rb _ si
-... | rb-red _ value x₁ x₂ x₃ t t₁ = t₁
-... | rb-black _ value x₁ t t₁ = t₁
-PGtoRBinvariant1 tree orig rb (tree ∷ rest) (s-left .tree .orig tree₁ x si) with PGtoRBinvariant1 _ orig rb _ si
-... | rb-red _ value x₁ x₂ x₃ t t₁ = t
-... | rb-black _ value x₁ t t₁ = t
-
-RBI-child-replaced : {n : Level} {A : Set n} (tr : bt (Color ∧ A)) (key : ℕ) →  RBtreeInvariant tr → RBtreeInvariant (child-replaced key tr)
-RBI-child-replaced {n} {A} leaf key rbi = rbi
-RBI-child-replaced {n} {A} (node key₁ value tr tr₁) key rbi with <-cmp key key₁
-... | tri< a ¬b ¬c = RBtreeLeftDown _ _ rbi
-... | tri≈ ¬a b ¬c = rbi
-... | tri> ¬a ¬b c = RBtreeRightDown _ _ rbi
-
---
--- create RBT invariant after findRBT, continue to replaceRBT
---
-createRBT : {n m : Level} {A : Set n } {t : Set m }
- → (key : ℕ) (value : A)
- → (tree0 : bt (Color ∧ A))
- → RBtreeInvariant tree0
- → treeInvariant tree0
- → (tree1 : bt (Color ∧ A))
- → (stack : List (bt (Color ∧ A)))
- → stackInvariant key tree1 tree0 stack
- → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key ) 
- → (exit : (stack : List ( bt (Color ∧ A))) (r : RBI key value tree0 stack ) → t ) → t
-createRBT {n} {m} {A} {t} key value orig rbi ti tree (x ∷ []) si P exit = crbt00 orig P refl where
-     crbt00 : (tree1 : bt (Color ∧ A)) → (tree ≡ leaf ) ∨ ( node-key tree ≡ just key ) → tree1 ≡ orig → t
-     crbt00 leaf P refl = exit (x ∷ []) record {  
-         tree = leaf
-         ; repl = node key ⟪ Red , value ⟫ leaf leaf
-         ; origti = ti
-         ; origrb = rbi
-         ; treerb = rb-leaf 
-         ; replrb = rb-red key value refl refl refl rb-leaf rb-leaf
-         ; si = subst (λ k → stackInvariant key k leaf _ ) crbt01 si
-         ; state = rotate leaf refl rbr-leaf
-         } where
-             crbt01 : tree ≡ leaf
-             crbt01 with si-property-last _ _ _ _ si | si-property1 si
-             ... | refl | refl = refl
-     crbt00 (node key₁ value₁ left right ) (case1 eq) refl with si-property-last _ _ _ _ si | si-property1 si
-     ... | refl | refl = ⊥-elim (bt-ne (sym eq))
-     crbt00 (node key₁ value₁ left right ) (case2 eq) refl with si-property-last _ _ _ _ si | si-property1 si
-     ... | refl | refl = exit (x ∷ []) record {  
-         tree = node key₁ value₁ left right
-         ; repl = node key₁ ⟪ proj1 value₁ , value ⟫ left right 
-         ; origti = ti
-         ; origrb = rbi
-         ; treerb = rbi
-         ; replrb = crbt03 value₁ rbi
-         ; si = si
-         ; state = rebuild refl (crbt01 value₁ ) (λ ()) crbt04
-         }  where 
-             crbt01 : (value₁ : Color ∧ A) → black-depth (node key₁ ⟪ proj1 value₁ , value ⟫ left right) ≡ black-depth (node key₁ value₁ left right)
-             crbt01 ⟪ Red , proj4 ⟫ = refl
-             crbt01 ⟪ Black , proj4 ⟫ = refl
-             crbt03 : (value₁ : Color ∧ A) → RBtreeInvariant (node key₁ value₁ left right) → RBtreeInvariant (node key₁ ⟪ proj1 value₁ , value ⟫ left right)
-             crbt03 ⟪ Red , proj4 ⟫ (rb-red .key₁ .proj4 x x₁ x₂ rbi rbi₁) = rb-red key₁ _ x x₁ x₂ rbi rbi₁
-             crbt03 ⟪ Black , proj4 ⟫ (rb-black .key₁ .proj4 x rbi rbi₁) = rb-black key₁ _ x rbi rbi₁
-             keq : ( just key₁ ≡ just key ) → key₁ ≡ key
-             keq refl = refl
-             crbt04 : replacedRBTree key value (node key₁ value₁ left right) (node key₁ ⟪ proj1 value₁ , value ⟫ left right)
-             crbt04 = subst (λ k → replacedRBTree k value (node key₁ value₁ left right) (node key₁ ⟪ proj1 value₁ , value ⟫ left right)) (keq eq) rbr-node
-createRBT {n} {m} {A} {t} key value orig rbi ti tree (x ∷ leaf ∷ stack) si P exit = ⊥-elim (si-property-parent-node _ _ _ si refl)
-createRBT {n} {m} {A} {t} key value orig rbi ti tree sp@(x ∷ node kp vp pleft pright ∷ stack) si P exit = crbt00 tree P refl where
-     crbt00 : (tree1 : bt (Color ∧ A)) → (tree ≡ leaf ) ∨ ( node-key tree ≡ just key ) → tree1 ≡ tree → t
-     crbt00 leaf P refl = exit sp record {  
-         tree = leaf
-         ; repl = node key ⟪ Red , value ⟫ leaf leaf
-         ; origti = ti
-         ; origrb = rbi
-         ; treerb = rb-leaf
-         ; replrb = rb-red key value refl refl refl rb-leaf rb-leaf
-         ; si = si
-         ; state = rotate leaf refl rbr-leaf
-         } 
-     crbt00 (node key₁ value₁ left right ) (case1 eq) refl = ⊥-elim (bt-ne (sym eq))
-     crbt00 (node key₁ value₁ left right ) (case2 eq) refl with si-property-last _ _ _ _ si | si-property1 si
-     ... | eq1 | eq2 = exit sp record {  
-         tree = node key₁ value₁ left right
-         ; repl = node key₁ ⟪ proj1 value₁ , value ⟫ left right 
-         ; origti = ti
-         ; origrb = rbi
-         ; treerb = treerb
-         ; replrb = crbt03 value₁ treerb
-         ; si = si
-         ; state = rebuild refl (crbt01 value₁ ) (λ ()) crbt04
-         }  where 
-             crbt01 : (value₁ : Color ∧ A) → black-depth (node key₁ ⟪ proj1 value₁ , value ⟫ left right) ≡ black-depth (node key₁ value₁ left right)
-             crbt01 ⟪ Red , proj4 ⟫ = refl
-             crbt01 ⟪ Black , proj4 ⟫ = refl
-             crbt03 : (value₁ : Color ∧ A) → RBtreeInvariant (node key₁ value₁ left right) → RBtreeInvariant (node key₁ ⟪ proj1 value₁ , value ⟫ left right)
-             crbt03 ⟪ Red , proj4 ⟫ (rb-red .key₁ .proj4 x x₁ x₂ rbi rbi₁) = rb-red key₁ _ x x₁ x₂ rbi rbi₁
-             crbt03 ⟪ Black , proj4 ⟫ (rb-black .key₁ .proj4 x rbi rbi₁) = rb-black key₁ _ x rbi rbi₁
-             keq : ( just key₁ ≡ just key ) → key₁ ≡ key
-             keq refl = refl
-             crbt04 : replacedRBTree key value (node key₁ value₁ left right) (node key₁ ⟪ proj1 value₁ , value ⟫ left right)
-             crbt04 = subst (λ k → replacedRBTree k value (node key₁ value₁ left right) (node key₁ ⟪ proj1 value₁ , value ⟫ left right)) (keq eq) rbr-node
-             treerb : RBtreeInvariant (node key₁ value₁ left right)
-             treerb = PGtoRBinvariant1 _ orig rbi _ si
-
---
---   rotate and rebuild replaceTree and rb-invariant
---
-replaceRBP : {n m : Level} {A : Set n} {t : Set m}
-     → (key : ℕ) → (value : A)
-     → (orig : bt (Color ∧ A))
-     → (stack : List (bt (Color ∧ A)))
-     → (r : RBI key value orig stack )
-     → (next :  (stack1 : List (bt (Color ∧ A)))
-        → (r : RBI key value orig stack1 )
-        → length stack1 < length stack  → t )
-     → (exit : (stack1 : List (bt (Color ∧ A)))
-        →  stack1 ≡ (orig ∷ [])
-        →  RBI key value orig stack1
-        → t ) → t
-replaceRBP {n} {m} {A} {t} key value orig stack r next exit = replaceRBP1 where
-    -- we have no grand parent
-    -- eq : stack₁ ≡ RBI.tree r ∷ orig ∷ []
-    -- change parent color ≡ Black and exit
-    -- one level stack, orig is parent of repl
-    repl = RBI.repl r
-    insertCase4 :  (tr0 : bt (Color ∧ A)) → tr0 ≡ orig
-       → (eq : stack ≡ RBI.tree r ∷ orig ∷ [])
-       → (rot : replacedRBTree key value (RBI.tree r) repl)
-       → ( color repl ≡ Red ) ∨ (color (RBI.tree r) ≡ color repl)
-       → stackInvariant key (RBI.tree r) orig stack
-       → t
-    insertCase4 leaf eq1 eq rot col si = ⊥-elim (rb04 eq eq1 si) where -- can't happen
-       rb04 : {stack : List ( bt ( Color ∧ A))} → stack ≡ RBI.tree r ∷ orig ∷ [] → leaf ≡ orig → stackInvariant key (RBI.tree r) orig stack →   ⊥
-       rb04  refl refl (s-right tree leaf tree₁ x si) = si-property2 _ (s-right tree leaf tree₁ x si) refl
-       rb04  refl refl (s-left tree₁ leaf tree x si) = si-property2 _  (s-left tree₁ leaf tree x si) refl
-    insertCase4  tr0@(node key₁ value₁ left right) refl eq rot col si with <-cmp key key₁
-    ... | tri< a ¬b ¬c = rb07 col where
-       rb04 : stackInvariant key (RBI.tree r) orig stack → stack ≡ RBI.tree r ∷ orig ∷ [] → tr0 ≡ orig → left ≡ RBI.tree r
-       rb04 (s-left tree₁ .(node key₁ value₁ left right) tree {key₂} x s-nil) refl refl = refl
-       rb04 (s-right tree .(node key₁ _ tree₁ tree) tree₁ x s-nil) refl refl with si-property1 si
-       ... | refl = ⊥-elim ( nat-<> x a  )
-       rb06 : black-depth repl ≡ black-depth right
-       rb06 = begin
-         black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-         black-depth (RBI.tree r) ≡⟨ cong black-depth (sym (rb04 si eq refl)) ⟩
-         black-depth left ≡⟨ (RBtreeEQ (RBI.origrb r)) ⟩
-         black-depth right ∎
-            where open ≡-Reasoning
-       rb08 :  (color (RBI.tree r) ≡ color repl) → RBtreeInvariant (node key₁ value₁ repl right)
-       rb08 ceq with proj1 value₁ in coeq
-       ... | Red = subst (λ k → RBtreeInvariant (node key₁ k repl right)) (cong (λ k → ⟪ k , _ ⟫) (sym coeq) )
-           (rb-red _ (proj2 value₁) rb09 (proj2 (RBtreeChildrenColorBlack _ _ (RBI.origrb r) coeq)) rb06 (RBI.replrb r)
-               (RBtreeRightDown _ _ (RBI.origrb r))) where
-           rb09 : color repl ≡ Black
-           rb09 = trans (trans (sym ceq) (sym (cong color (rb04 si eq refl) ))) (proj1 (RBtreeChildrenColorBlack _ _ (RBI.origrb r) coeq))
-       ... | Black = subst (λ k → RBtreeInvariant (node key₁ k repl right)) (cong (λ k → ⟪ k , _ ⟫) (sym coeq) )
-           (rb-black _ (proj2 value₁) rb06 (RBI.replrb r) (RBtreeRightDown _ _ (RBI.origrb r)))
-       rb07 : ( color repl ≡ Red ) ∨ (color (RBI.tree r) ≡ color repl) → t
-       rb07 (case2 cc ) = exit  (orig ∷ []) refl record {
-         tree = orig
-         ; repl = node key₁ value₁ repl right
-         ; origti = RBI.origti r
-         ; origrb = RBI.origrb r
-         ; treerb = RBI.origrb r
-         ; replrb = rb08 cc
-         ; si = s-nil
-         ; state = top-black  refl (case1 (rbr-left (trans (cong color (rb04 si eq refl)) cc) a (subst (λ k → replacedRBTree key value k repl) (sym (rb04 si eq refl)) rot)))
-         }
-       rb07 (case1 repl-red) = exit  (orig ∷ []) refl record {
-         tree = orig
-         ; repl = to-black (node key₁ value₁ repl right)
-         ; origti = RBI.origti r
-         ; origrb = RBI.origrb r
-         ; treerb = RBI.origrb r
-         ; replrb = rb-black _ _ rb06 (RBI.replrb r) (RBtreeRightDown _ _ (RBI.origrb r))
-         ; si = s-nil
-         ; state = top-black  refl (case2 (rbr-black-left repl-red a (subst (λ k → replacedRBTree key value k repl) (sym (rb04 si eq refl)) rot)))
-         }
-    ... | tri≈ ¬a b ¬c = ⊥-elim ( si-property-pne _ _ stack eq si b ) -- can't happen
-    ... | tri> ¬a ¬b c = rb07 col where
-       rb04 : stackInvariant key (RBI.tree r) orig stack → stack ≡ RBI.tree r ∷ orig ∷ [] → tr0 ≡ orig → right ≡ RBI.tree r
-       rb04 (s-right tree .(node key₁ _ tree₁ tree) tree₁ x s-nil) refl refl = refl
-       rb04 (s-left tree₁ .(node key₁ value₁ left right) tree {key₂} x si) refl refl with si-property1 si
-       ... | refl = ⊥-elim ( nat-<> x c  )
-       rb06 : black-depth repl ≡ black-depth left
-       rb06 = begin
-         black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-         black-depth (RBI.tree r) ≡⟨ cong black-depth (sym (rb04 si eq refl)) ⟩
-         black-depth right ≡⟨ (sym (RBtreeEQ (RBI.origrb r))) ⟩
-         black-depth left ∎
-            where open ≡-Reasoning
-       rb08 :  (color (RBI.tree r) ≡ color repl) → RBtreeInvariant (node key₁ value₁ left repl )
-       rb08 ceq with proj1 value₁ in coeq
-       ... | Red = subst (λ k → RBtreeInvariant (node key₁ k left repl )) (cong (λ k → ⟪ k , _ ⟫) (sym coeq) )
-           (rb-red _ (proj2 value₁) (proj1 (RBtreeChildrenColorBlack _ _ (RBI.origrb r) coeq)) rb09 (sym rb06)
-               (RBtreeLeftDown _ _ (RBI.origrb r))(RBI.replrb r)) where
-           rb09 : color repl ≡ Black
-           rb09 = trans (trans (sym ceq) (sym (cong color (rb04 si eq refl) ))) (proj2 (RBtreeChildrenColorBlack _ _ (RBI.origrb r) coeq))
-       ... | Black = subst (λ k → RBtreeInvariant (node key₁ k left repl )) (cong (λ k → ⟪ k , _ ⟫) (sym coeq) )
-           (rb-black _ (proj2 value₁) (sym rb06)  (RBtreeLeftDown _ _ (RBI.origrb r)) (RBI.replrb r))
-       rb07 : ( color repl ≡ Red ) ∨ (color (RBI.tree r) ≡ color repl) → t
-       rb07 (case2 cc ) = exit  (orig ∷ []) refl record {
-         tree = orig
-         ; repl = node key₁ value₁ left repl 
-         ; origti = RBI.origti r
-         ; origrb = RBI.origrb r
-         ; treerb = RBI.origrb r
-         ; replrb = rb08 cc
-         ; si = s-nil
-         ; state = top-black  refl (case1 (rbr-right (trans (cong color (rb04 si eq refl)) cc) c (subst (λ k → replacedRBTree key value k repl) (sym (rb04 si eq refl)) rot)))
-         }
-       rb07 (case1 repl-red ) = exit  (orig ∷ [])  refl record {
-         tree = orig
-         ; repl = to-black (node key₁ value₁ left repl)
-         ; origti = RBI.origti r
-         ; origrb = RBI.origrb r
-         ; treerb = RBI.origrb r
-         ; replrb = rb-black _ _ (sym rb06) (RBtreeLeftDown _ _ (RBI.origrb r)) (RBI.replrb r)
-         ; si = s-nil
-         ; state = top-black refl (case2 (rbr-black-right repl-red c (subst (λ k → replacedRBTree key value k repl) (sym (rb04 si eq refl)) rot)))
-         }
-    rebuildCase : (ceq : color (RBI.tree r) ≡ color repl)
-       → (bdepth-eq : black-depth repl ≡ black-depth (RBI.tree r))
-       → (¬ RBI.tree r ≡ leaf)
-       → (rot       : replacedRBTree key value (RBI.tree r) repl ) → t
-    rebuildCase ceq bdepth-eq ¬leaf rot with stackToPG (RBI.tree r) orig stack (RBI.si r)
-    ... | case1 x = exit stack x r  where  -- single node case
-        rb00 : stack ≡ orig ∷ [] → orig ≡ RBI.tree r
-        rb00 refl = si-property1 (RBI.si r)
-    ... | case2 (case1 x) = insertCase4 orig refl x rot (case2 ceq) (RBI.si r)   -- one level stack, orig is parent of repl
-    ... | case2 (case2 pg) = rebuildCase1 pg where
-       rb00 : (pg : PG (Color ∧ A) key (RBI.tree r) stack) → stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-       rb00 pg = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-       treerb : (pg : PG (Color ∧ A) key (RBI.tree r) stack) → RBtreeInvariant (PG.parent pg)
-       treerb pg = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (rb00 pg))
-       rb08 : (pg : PG (Color ∧ A) key (RBI.tree r) stack) → treeInvariant (PG.parent pg)
-       rb08 pg = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ (rb00 pg))
-       rebuildCase1 : (PG (Color ∧ A) key (RBI.tree r) stack) → t
-       rebuildCase1 pg with PG.pg pg
-       ... | s2-s1p2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = rebuildCase2 where
-          rebuildCase2 : t
-          rebuildCase2 = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-              tree = PG.parent pg
-              ; repl = rb01
-              ; origti = RBI.origti r
-              ; origrb = RBI.origrb r
-              ; treerb = treerb pg
-              ; replrb = rb02
-              ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-              ; state = rebuild (cong color x) rb06 (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))  (subst (λ k → replacedRBTree key value k rb01) (sym x) (rbr-left ceq rb04 rot))
-             } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-               rb01 : bt (Color ∧ A)
-               rb01 = node kp vp repl n1 
-               rb03 : black-depth n1 ≡ black-depth repl
-               rb03 = trans (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)))) (RB-repl→eq _ _ (RBI.treerb r) rot)
-               rb02 : RBtreeInvariant rb01
-               rb02 with subst (λ k → RBtreeInvariant k) x (treerb pg)
-               ... | rb-red .kp value cx cx₁ ex₂ t t₁ = rb-red kp value (trans (sym ceq) cx) cx₁ (sym rb03) (RBI.replrb r) t₁
-               ... | rb-black .kp value ex t t₁ = rb-black kp value (sym rb03) (RBI.replrb r) t₁
-               rb05 : treeInvariant (node kp vp (RBI.tree r) n1 )
-               rb05 = subst (λ k → treeInvariant k) x (rb08 pg)
-               rb04 : key < kp
-               rb04 = lt
-               rb06 : black-depth rb01 ≡ black-depth (PG.parent pg)
-               rb06 = trans (rb07 vp) ( cong black-depth (sym x) ) where
-                   rb07 : (vp : Color ∧ A) → black-depth (node kp vp repl n1) ≡ black-depth (node kp vp (RBI.tree r) n1 )
-                   rb07 ⟪ Black  , proj4 ⟫ = cong (λ k → suc (k ⊔ black-depth n1 )) bdepth-eq
-                   rb07 ⟪ Red  , proj4 ⟫ = cong (λ k → (k ⊔ black-depth n1  )) bdepth-eq
-       ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = rebuildCase2 where
-          rebuildCase2 : t
-          rebuildCase2 = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-              tree = PG.parent pg
-              ; repl = rb01
-              ; origti = RBI.origti r
-              ; origrb = RBI.origrb r
-              ; treerb = treerb pg
-              ; replrb = rb02
-              ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-              ; state = rebuild (cong color x) rb06 (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → replacedRBTree key value k rb01) (sym x) (rbr-right ceq rb04 rot))
-             } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-               rb01 : bt (Color ∧ A)
-               rb01 = node kp vp n1 repl
-               rb03 : black-depth n1 ≡ black-depth repl
-               rb03 = trans (RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg))) ((RB-repl→eq _ _ (RBI.treerb r) rot))
-               rb02 : RBtreeInvariant rb01
-               rb02 with subst (λ k → RBtreeInvariant k) x (treerb pg)
-               ... | rb-red .kp value cx cx₁ ex₂ t t₁ = rb-red kp value cx (trans (sym ceq) cx₁) rb03 t (RBI.replrb r)
-               ... | rb-black .kp value ex t t₁ = rb-black kp value rb03 t (RBI.replrb r)
-               rb05 : treeInvariant (node kp vp n1 (RBI.tree r) )
-               rb05 = subst (λ k → treeInvariant k) x (rb08 pg)
-               rb04 : kp < key
-               rb04 = lt
-               rb06 : black-depth rb01 ≡ black-depth (PG.parent pg)
-               rb06 = trans (rb07 vp) ( cong black-depth (sym x) ) where
-                   rb07 : (vp : Color ∧ A) → black-depth (node kp vp n1 repl) ≡ black-depth (node kp vp n1 (RBI.tree r))
-                   rb07 ⟪ Black  , proj4 ⟫ = cong (λ k → suc (black-depth n1 ⊔ k)) bdepth-eq
-                   rb07 ⟪ Red  , proj4 ⟫ = cong (λ k → (black-depth n1 ⊔ k)) bdepth-eq
-       ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = rebuildCase2 where
-          rebuildCase2 : t
-          rebuildCase2 = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-              tree = PG.parent pg
-              ; repl = rb01
-              ; origti = RBI.origti r
-              ; origrb = RBI.origrb r
-              ; treerb = treerb pg
-              ; replrb = rb02
-              ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-              ; state = rebuild (cong color x) rb06 (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → replacedRBTree key value k rb01) (sym x) (rbr-left ceq rb04 rot))
-             } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-               rb01 : bt (Color ∧ A)
-               rb01 = node kp vp repl n1
-               rb03 : black-depth n1 ≡ black-depth repl 
-               rb03 = trans (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)))) ((RB-repl→eq _ _ (RBI.treerb r) rot))
-               rb02 : RBtreeInvariant rb01
-               rb02 with subst (λ k → RBtreeInvariant k) x (treerb pg)
-               ... | rb-red .kp value cx cx₁ ex₂ t t₁ = rb-red kp value (trans (sym ceq) cx) cx₁ (sym rb03) (RBI.replrb r) t₁
-               ... | rb-black .kp value ex t t₁ = rb-black kp value (sym rb03) (RBI.replrb r) t₁
-               rb05 : treeInvariant (node kp vp (RBI.tree r) n1)
-               rb05 = subst (λ k → treeInvariant k) x (rb08 pg)
-               rb04 : key < kp
-               rb04 = lt
-               rb06 : black-depth rb01 ≡ black-depth (PG.parent pg)
-               rb06 = trans (rb07 vp) ( cong black-depth (sym x) ) where
-                   rb07 : (vp : Color ∧ A) → black-depth (node kp vp repl n1) ≡ black-depth (node kp vp (RBI.tree r) n1)
-                   rb07 ⟪ Black  , proj4 ⟫ = cong (λ k → suc (k ⊔ black-depth n1 )) bdepth-eq
-                   rb07 ⟪ Red  , proj4 ⟫ = cong (λ k → (k ⊔ black-depth n1 ))  bdepth-eq
-       ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = rebuildCase2 where
-          rebuildCase2 : t
-          rebuildCase2 = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-              tree = PG.parent pg
-              ; repl = rb01
-              ; origti = RBI.origti r
-              ; origrb = RBI.origrb r
-              ; treerb = treerb pg
-              ; replrb = rb02
-              ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-              ; state = rebuild (cong color x) rb06 (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → replacedRBTree key value k rb01) (sym x) (rbr-right ceq rb04 rot))
-             } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-               rb01 : bt (Color ∧ A)
-               rb01 = node kp vp n1 repl
-               rb03 : black-depth n1 ≡ black-depth repl
-               rb03 = trans (RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg))) ((RB-repl→eq _ _ (RBI.treerb r) rot))
-               rb02 : RBtreeInvariant rb01
-               rb02 with subst (λ k → RBtreeInvariant k) x (treerb pg)
-               ... | rb-red .kp value cx cx₁ ex₂ t t₁ = rb-red kp value cx (trans (sym ceq) cx₁) rb03 t (RBI.replrb r)
-               ... | rb-black .kp value ex t t₁ = rb-black kp value rb03 t (RBI.replrb r)
-               rb05 : treeInvariant (node kp vp n1 (RBI.tree r))
-               rb05 = subst (λ k → treeInvariant k) x (rb08 pg)
-               rb04 : kp < key
-               rb04 = si-property-> ¬leaf rb05 (subst (λ k → stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ k ∷ PG.grand pg ∷ PG.rest pg)) x (rb00 pg))
-               rb06 : black-depth rb01 ≡ black-depth (PG.parent pg)
-               rb06 = trans (rb07 vp) ( cong black-depth (sym x) ) where
-                   rb07 : (vp : Color ∧ A) → black-depth (node kp vp n1 repl) ≡ black-depth (node kp vp n1 (RBI.tree r))
-                   rb07 ⟪ Black  , proj4 ⟫ = cong (λ k → suc (black-depth n1 ⊔ k)) bdepth-eq
-                   rb07 ⟪ Red  , proj4 ⟫ = cong (λ k → (black-depth n1 ⊔ k)) bdepth-eq
-    --
-    -- both parent and uncle are Red, rotate then goto rebuild
-    --
-    insertCase5 : (repl1 : bt (Color ∧ A)) → repl1 ≡ repl
-       → (pg : PG (Color ∧ A) key (RBI.tree r) stack)
-       → (rot : replacedRBTree key value (RBI.tree r) repl)
-       → color repl ≡ Red → color (PG.uncle pg) ≡ Black → color (PG.parent pg) ≡ Red → t
-    insertCase5 leaf eq pg rot repl-red uncle-black pcolor = ⊥-elim ( rb00 repl repl-red (cong color (sym eq))) where
-        rb00 : (repl : bt (Color ∧ A)) → color repl ≡ Red → color repl ≡ Black → ⊥
-        rb00 (node key ⟪ Black , proj4 ⟫ repl repl₁) () eq1
-        rb00 (node key ⟪ Red , proj4 ⟫ repl repl₁) eq ()
-    insertCase5 (node rkey vr rp-left rp-right) eq pg rot repl-red uncle-black pcolor = insertCase51 where
-        rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-        rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-        rb15 : suc (length (PG.rest pg)) < length stack
-        rb15 = begin
-              suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
-              length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
-              length stack ∎
-                 where open ≤-Reasoning
-        rb02 : RBtreeInvariant (PG.grand pg)
-        rb02 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
-        rb09 : RBtreeInvariant (PG.parent pg)
-        rb09 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ rb00)
-        rb08 : treeInvariant (PG.parent pg)
-        rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
-
-        insertCase51 : t
-        insertCase51 with PG.pg pg
-        ... | s2-s1p2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase52 where
-          insertCase52 : t
-          insertCase52 = next (PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.grand pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = rb02
-            ; replrb = subst (λ k → RBtreeInvariant k) rb10 (rb-black _ _ rb18 (RBI.replrb r) (rb-red _ _ rb16 uncle-black rb19 rb06 rb05))
-            ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-            ; state = rebuild (trans (cong color x₁) (cong proj1 (sym rb14))) rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
-           } rb15 where
-            rb01 : bt (Color ∧ A)
-            rb01 = to-black (node kp vp (node rkey vr rp-left rp-right) (to-red (node kg vg n1 (PG.uncle pg))))
-            rb04 : key < kp
-            rb04 = lt
-            rb16 : color n1 ≡ Black
-            rb16 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
-            rb13 : ⟪ Red , proj2 vp ⟫ ≡ vp
-            rb13 with subst (λ k → color k ≡ Red ) x pcolor
-            ... | refl = refl
-            rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
-            rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case1 pcolor)
-            ... | refl = refl
-            rb03 : replacedRBTree key value (node kg _ (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) (PG.uncle pg))
-                (node kp ⟪ Black , proj2 vp ⟫  repl (node kg ⟪ Red , proj2 vg ⟫ n1 (PG.uncle pg)))
-            rb03 = rbr-rotate-ll repl-red rb04 rot
-            rb10 : node kp ⟪ Black , proj2 vp ⟫ repl (node kg ⟪ Red , proj2 vg ⟫ n1 (PG.uncle pg)) ≡ rb01
-            rb10 = begin
-               to-black (node kp vp repl (to-red (node kg vg n1 (PG.uncle pg)))) ≡⟨ cong (λ k → node _ _ k _) (sym eq) ⟩
-               rb01 ∎ where open ≡-Reasoning
-            rb12 : node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) (PG.uncle pg) ≡ PG.grand pg
-            rb12 = begin
-                 node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) (PG.uncle pg)
-                    ≡⟨ cong₂ (λ j k → node kg j (node kp k (RBI.tree r) n1) (PG.uncle pg) ) rb14 rb13 ⟩
-                 node kg vg _ (PG.uncle pg) ≡⟨ cong (λ k → node _ _ k _) (sym x) ⟩
-                 node kg vg (PG.parent pg) (PG.uncle pg) ≡⟨ sym x₁ ⟩
-                 PG.grand pg ∎ where open ≡-Reasoning
-            rb11 : replacedRBTree key value (PG.grand pg) rb01
-            rb11 = subst₂ (λ j k → replacedRBTree key value j k) rb12 rb10 rb03
-            rb05 : RBtreeInvariant (PG.uncle pg)
-            rb05 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02)
-            rb06 : RBtreeInvariant n1
-            rb06 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x rb09)
-            rb19 : black-depth n1 ≡ black-depth (PG.uncle pg)
-            rb19 = trans (sym ( proj2 (red-children-eq x (sym (cong proj1 rb13))  rb09) )) (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02))
-            rb18 : black-depth repl ≡ black-depth n1 ⊔ black-depth (PG.uncle pg)
-            rb18 = begin
-               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-               black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09) ⟩
-               black-depth n1 ≡⟨ sym (⊔-idem (black-depth n1)) ⟩
-               black-depth n1 ⊔ black-depth n1 ≡⟨ cong (λ k → black-depth n1 ⊔ k) rb19 ⟩
-               black-depth n1 ⊔ black-depth (PG.uncle pg) ∎ where open ≡-Reasoning
-            rb17 : suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg))) ≡ black-depth (PG.grand pg)
-            rb17 = begin 
-                suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg))) 
-                     ≡⟨ cong₂ (λ j k → suc (black-depth j ⊔ k)) eq (sym rb18) ⟩
-                suc (black-depth repl ⊔ black-depth repl) ≡⟨ ⊔-idem _ ⟩
-                suc (black-depth repl ) ≡⟨ cong suc (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
-                suc (black-depth (RBI.tree r) ) ≡⟨ cong suc (sym (proj1 (red-children-eq x (cong proj1 (sym rb13)) rb09))) ⟩
-                suc (black-depth (PG.parent pg) ) ≡⟨ sym (proj1 (black-children-eq refl (cong proj1 (sym rb14)) (subst (λ k → RBtreeInvariant k) x₁ rb02))) ⟩
-                black-depth (node kg vg (PG.parent pg) (PG.uncle pg)) ≡⟨ cong black-depth (sym x₁) ⟩
-                black-depth (PG.grand pg) ∎ where open ≡-Reasoning
-                -- outer case, repl  is not decomposed
-                -- lt          : key < kp
-                -- x           : PG.parent pg ≡ node kp vp (RBI.tree r) n1
-                -- x₁          : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
-                -- eq          : node rkey vr rp-left rp-right ≡ RBI.repl r
-        ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase52 where
-          insertCase52 : t
-          insertCase52 = next (PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.grand pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = rb02
-            ; replrb = rb10
-            ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-            ; state = rebuild rb33 rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
-           } rb15 where
-                -- inner case, repl  is decomposed
-                -- lt          : kp < key
-                -- x           : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
-                -- x₁          : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
-                -- eq          : node rkey vr rp-left rp-right ≡ RBI.repl r
-            rb01 : bt (Color ∧ A)
-            rb01 = to-black (node rkey vr (node kp vp n1 rp-left) (to-red (node kg vg rp-right (PG.uncle pg))))
-            rb04 : kp < key
-            rb04 = lt
-            rb21 : key < kg   -- this can be a part of ParentGand relation
-            rb21 = si-property-< (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r) 
-                 (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)))) 
-                 (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
-            rb16 : color n1 ≡ Black
-            rb16 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
-            rb13 : ⟪ Red , proj2 vp ⟫ ≡ vp
-            rb13 with subst (λ k → color k ≡ Red ) x pcolor
-            ... | refl = refl
-            rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
-            rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case1 pcolor)
-            ... | refl = refl
-            rb33 : color (PG.grand pg) ≡ Black
-            rb33 = subst (λ k → color k ≡ Black ) (sym x₁) (sym (cong proj1 rb14))
-            rb23 :  vr ≡ ⟪ Red , proj2 vr ⟫ 
-            rb23 with subst (λ k → color k ≡ Red ) (sym eq) repl-red
-            ... | refl = refl
-            rb20 : color rp-right ≡ Black
-            rb20 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r) ) (cong proj1 rb23))
-            rb03 : replacedRBTree key value (node kg _ (node kp _ n1 (RBI.tree r)) (PG.uncle pg))
-               (node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫  n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)))
-            rb03 = rbr-rotate-lr rp-left rp-right kg kp rkey rb20 rb04 rb21  
-                (subst (λ k → replacedRBTree key value (RBI.tree r) k) (trans (sym eq) (cong (λ k → node rkey k rp-left rp-right) rb23 )) rot )
-            rb24 : node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r)) (PG.uncle pg) ≡ PG.grand pg
-            rb24 = trans (trans (cong₂ (λ j k → node kg j (node kp k n1 (RBI.tree r)) (PG.uncle pg)) rb14 rb13 ) (cong (λ k → node kg vg k (PG.uncle pg)) (sym x))) (sym x₁)
-            rb25 : node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)) ≡ rb01
-            rb25 = begin 
-                node rkey ⟪ Black , proj2 vr ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)) 
-                     ≡⟨ cong (λ k → node _ _ (node kp k  n1 rp-left) _ ) rb13 ⟩
-                node rkey ⟪ Black , proj2 vr ⟫ (node kp vp n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg))  ≡⟨ refl  ⟩
-                rb01 ∎ where open ≡-Reasoning
-            rb11 : replacedRBTree key value (PG.grand pg) rb01
-            rb11 = subst₂ (λ j k → replacedRBTree key value j k) rb24 rb25 rb03
-            rb05 : RBtreeInvariant (PG.uncle pg)
-            rb05 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02)
-            rb06 : RBtreeInvariant n1
-            rb06 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb09)
-            rb26 : RBtreeInvariant rp-left
-            rb26 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
-            rb28 : RBtreeInvariant rp-right
-            rb28 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
-            rb31 : RBtreeInvariant (node rkey vr rp-left rp-right )
-            rb31 = subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)
-            rb18 : black-depth rp-right ≡ black-depth (PG.uncle pg)
-            rb18 = begin
-                black-depth rp-right ≡⟨ sym ( proj2 (red-children-eq1 (sym eq) repl-red (RBI.replrb r) )) ⟩
-                black-depth (RBI.repl r) ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                black-depth (RBI.tree r) ≡⟨ sym (proj2 (red-children-eq1 x pcolor rb09) ) ⟩
-                black-depth (PG.parent pg) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02 ) ⟩
-                black-depth (PG.uncle pg) ∎ where open ≡-Reasoning
-            rb27 : black-depth n1 ≡ black-depth rp-left
-            rb27 = begin
-               black-depth n1 ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09) ⟩
-               black-depth (RBI.tree r) ≡⟨ RB-repl→eq _ _ (RBI.treerb r) rot ⟩
-               black-depth (RBI.repl r) ≡⟨ proj1 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
-               black-depth rp-left ∎ 
-                  where open ≡-Reasoning
-            rb19 : black-depth (node kp vp n1 rp-left) ≡ black-depth rp-right ⊔ black-depth (PG.uncle pg)
-            rb19 = begin
-                black-depth (node kp vp n1 rp-left) ≡⟨ black-depth-resp A (node kp vp n1 rp-left) (node kp vp rp-left rp-left)  refl refl refl rb27 refl ⟩
-                black-depth (node kp vp rp-left rp-left) ≡⟨ black-depth-resp A (node kp vp rp-left rp-left) (node rkey vr rp-left rp-right) 
-                     refl refl (trans (sym (cong proj1 rb13)) (sym (cong proj1 rb23))) refl (RBtreeEQ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))) ⟩
-                black-depth (node rkey vr rp-left rp-right) ≡⟨ black-depth-cong A eq ⟩
-                black-depth (RBI.repl r) ≡⟨ proj2 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
-                black-depth rp-right ≡⟨ sym ( ⊔-idem _ ) ⟩
-                black-depth rp-right ⊔ black-depth rp-right ≡⟨ cong (λ k → black-depth rp-right ⊔ k) rb18 ⟩
-                black-depth rp-right ⊔ black-depth (PG.uncle pg) ∎
-                  where open ≡-Reasoning
-            rb29 : color n1 ≡ Black
-            rb29 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (sym (cong proj1 rb13)) )
-            rb30 : color rp-left ≡ Black
-            rb30 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)) (cong proj1 rb23))
-            rb32 : suc (black-depth (PG.uncle pg)) ≡ black-depth (PG.grand pg)
-            rb32 = sym (proj2 ( black-children-eq1 x₁ rb33 rb02 ))
-            rb10 : RBtreeInvariant (node rkey ⟪ Black , proj2 vr ⟫ (node kp vp n1 rp-left) (node kg ⟪ Red , proj2 vg ⟫ rp-right (PG.uncle pg)))
-            rb10 = rb-black _ _ rb19 (rbi-from-red-black _ _ kp vp rb06 rb26 rb27 rb29 rb30 rb13) (rb-red _ _ rb20 uncle-black rb18 rb28 rb05)
-            rb17 : suc (black-depth (node kp vp n1 rp-left) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡ black-depth (PG.grand pg)
-            rb17 = begin
-                 suc (black-depth (node kp vp n1 rp-left) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡⟨ cong (λ k → suc (k ⊔ _)) rb19 ⟩
-                 suc ((black-depth rp-right ⊔ black-depth (PG.uncle pg)) ⊔ (black-depth rp-right ⊔ black-depth (PG.uncle pg))) ≡⟨ cong suc ( ⊔-idem _) ⟩
-                 suc (black-depth rp-right ⊔ black-depth (PG.uncle pg))  ≡⟨ cong (λ k → suc (k ⊔ _)) rb18 ⟩
-                 suc (black-depth (PG.uncle pg) ⊔ black-depth (PG.uncle pg)) ≡⟨ cong suc (⊔-idem _) ⟩
-                 suc (black-depth (PG.uncle pg))  ≡⟨ rb32 ⟩
-                 black-depth (PG.grand pg) ∎
-                 where open ≡-Reasoning
-        ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase52 where
-          insertCase52 : t
-          insertCase52 = next (PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.grand pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = rb02
-            ; replrb = rb10
-            ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-            ; state = rebuild rb33 rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
-           } rb15 where
-                -- inner case, repl  is decomposed
-                -- lt          : key < kp
-                -- x           : PG.parent pg ≡ node kp vp (RBI.tree r) n1
-                -- x₁          : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
-                -- eq          : node rkey vr rp-left rp-right ≡ RBI.repl r
-            rb01 : bt (Color ∧ A)
-            rb01 = to-black (node rkey vr (to-red (node kg vg (PG.uncle pg) rp-left )) (node kp vp rp-right n1))
-            rb04 : key < kp
-            rb04 = lt
-            rb21 : kg < key   -- this can be a part of ParentGand relation
-            rb21 = si-property-> (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r) 
-                 (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)))) 
-                 (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
-            rb16 : color n1 ≡ Black
-            rb16 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
-            rb13 : ⟪ Red , proj2 vp ⟫ ≡ vp
-            rb13 with subst (λ k → color k ≡ Red ) x pcolor
-            ... | refl = refl
-            rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
-            rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case2 pcolor)
-            ... | refl = refl
-            rb33 : color (PG.grand pg) ≡ Black
-            rb33 = subst (λ k → color k ≡ Black ) (sym x₁) (sym (cong proj1 rb14))
-            rb23 :  vr ≡ ⟪ Red , proj2 vr ⟫ 
-            rb23 with subst (λ k → color k ≡ Red ) (sym eq) repl-red
-            ... | refl = refl
-            rb20 : color rp-right ≡ Black
-            rb20 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r) ) (cong proj1 rb23))
-            rb03 : replacedRBTree key value (node kg _ (PG.uncle pg) (node kp _ (RBI.tree r) n1 ))
-               (node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left ) (node kp ⟪ Red , proj2 vp ⟫  rp-right n1 ))
-            rb03 = rbr-rotate-rl rp-left rp-right kg kp rkey rb20 rb21 rb04
-                (subst (λ k → replacedRBTree key value (RBI.tree r) k) (trans (sym eq) (cong (λ k → node rkey k rp-left rp-right) rb23 )) rot )
-            rb24 : node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) ≡ PG.grand pg
-            rb24 = begin
-               node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) 
-                   ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k (RBI.tree r) n1) ) rb14 rb13 ⟩
-               node kg vg (PG.uncle pg) (node kp vp (RBI.tree r) n1) ≡⟨ cong (λ k → node kg vg (PG.uncle pg) k ) (sym x) ⟩
-               node kg vg (PG.uncle pg) (PG.parent pg) ≡⟨ sym x₁ ⟩
-               PG.grand pg ∎ where open ≡-Reasoning
-            rb25 : node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp ⟪ Red , proj2 vp ⟫ rp-right n1) ≡ rb01
-            rb25 = begin 
-                node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp ⟪ Red , proj2 vp ⟫ rp-right n1) 
-                        ≡⟨ cong (λ k → node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp k rp-right n1)) rb13  ⟩
-                node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left) (node kp vp rp-right n1)  ≡⟨ refl ⟩
-                rb01 ∎ where open ≡-Reasoning
-            rb11 : replacedRBTree key value (PG.grand pg) rb01
-            rb11 = subst₂ (λ j k → replacedRBTree key value j k) rb24 rb25 rb03
-            rb05 : RBtreeInvariant (PG.uncle pg)
-            rb05 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02)
-            rb06 : RBtreeInvariant n1
-            rb06 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x rb09)
-            rb26 : RBtreeInvariant rp-left
-            rb26 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
-            rb28 : RBtreeInvariant rp-right
-            rb28 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r))
-            rb31 : RBtreeInvariant (node rkey vr rp-left rp-right )
-            rb31 = subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)
-            rb18 : black-depth (PG.uncle pg) ≡ black-depth rp-left
-            rb18 = sym ( begin
-                black-depth rp-left ≡⟨ sym ( proj1 (red-children-eq1 (sym eq) repl-red (RBI.replrb r) )) ⟩
-                black-depth (RBI.repl r) ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                black-depth (RBI.tree r) ≡⟨ sym (proj1 (red-children-eq1 x pcolor rb09) ) ⟩
-                black-depth (PG.parent pg) ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02 )) ⟩
-                black-depth (PG.uncle pg) ∎ ) where open ≡-Reasoning
-            rb27 : black-depth rp-right ≡ black-depth n1
-            rb27 = sym ( begin
-               black-depth n1 ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09)) ⟩
-               black-depth (RBI.tree r) ≡⟨ RB-repl→eq _ _ (RBI.treerb r) rot ⟩
-               black-depth (RBI.repl r) ≡⟨ proj2 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
-               black-depth rp-right ∎ )
-                  where open ≡-Reasoning
-            rb19 : black-depth (PG.uncle pg) ⊔ black-depth rp-left ≡ black-depth (node kp vp rp-right n1)
-            rb19 = sym ( begin
-                black-depth (node kp vp rp-right n1)  ≡⟨ black-depth-resp A (node kp vp rp-right n1) (node kp vp rp-right rp-right)  refl refl refl refl (sym rb27) ⟩
-                black-depth (node kp vp rp-right rp-right) ≡⟨ black-depth-resp A (node kp vp rp-right rp-right) (node rkey vr rp-left rp-right) 
-                     refl refl (trans (sym (cong proj1 rb13)) (sym (cong proj1 rb23))) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)))) refl ⟩
-                black-depth (node rkey vr rp-left rp-right) ≡⟨ black-depth-cong A eq ⟩
-                black-depth (RBI.repl r) ≡⟨ proj1 (red-children-eq1 (sym eq) repl-red (RBI.replrb r)) ⟩
-                black-depth rp-left ≡⟨ sym ( ⊔-idem _ ) ⟩
-                black-depth  rp-left ⊔ black-depth rp-left ≡⟨ cong (λ k → k ⊔ black-depth rp-left ) (sym rb18) ⟩
-                black-depth (PG.uncle pg) ⊔ black-depth rp-left ∎ )
-                  where open ≡-Reasoning
-            rb29 : color n1 ≡ Black
-            rb29 = proj2 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (sym (cong proj1 rb13)) )
-            rb30 : color rp-left ≡ Black
-            rb30 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) (sym eq) (RBI.replrb r)) (cong proj1 rb23))
-            rb32 : suc (black-depth (PG.uncle pg)) ≡ black-depth (PG.grand pg)
-            rb32 = sym (proj1 ( black-children-eq1 x₁ rb33 rb02 ))
-            rb10 : RBtreeInvariant (node rkey ⟪ Black , proj2 vr ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) rp-left ) (node kp vp rp-right n1) )
-            rb10 = rb-black _ _ rb19 (rb-red _ _ uncle-black rb30 rb18 rb05 rb26 ) (rbi-from-red-black _ _ _ _ rb28 rb06 rb27 rb20 rb16 rb13 )
-            rb17 : suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ⊔ black-depth (node kp vp rp-right n1)) ≡ black-depth (PG.grand pg)
-            rb17 = begin
-                 suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ⊔ black-depth (node kp vp rp-right n1)) ≡⟨ cong (λ k → suc (_ ⊔ k)) (sym rb19) ⟩
-                 suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ⊔ (black-depth (PG.uncle pg) ⊔ black-depth rp-left)) ≡⟨ cong suc ( ⊔-idem _) ⟩ 
-                 suc (black-depth (PG.uncle pg) ⊔ black-depth rp-left ) ≡⟨ cong (λ k → suc (_ ⊔ k)) (sym rb18) ⟩
-                 suc (black-depth (PG.uncle pg) ⊔ black-depth (PG.uncle pg)) ≡⟨ cong suc (⊔-idem _) ⟩
-                 suc (black-depth (PG.uncle pg))  ≡⟨ rb32 ⟩
-                 black-depth (PG.grand pg) ∎
-                    where open ≡-Reasoning
-        ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase52 where
-          insertCase52 : t
-          insertCase52 = next (PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.grand pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = rb02
-            ; replrb = subst (λ k → RBtreeInvariant k) rb10 (rb-black _ _ rb18 (rb-red _ _ uncle-black rb16 rb19 rb05 rb06) (RBI.replrb r) )
-            ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-            ; state = rebuild rb33 rb17 (subst (λ k → ¬ (k ≡ leaf)) (sym x₁) (λ ())) rb11
-           } rb15 where
-                -- outer case, repl  is not decomposed
-                -- lt          : kp < key 
-                -- x           : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
-                -- x₁          : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
-            rb01 : bt (Color ∧ A)
-            rb01 = to-black (node kp vp  (to-red (node kg vg (PG.uncle pg) n1) )(node rkey vr rp-left rp-right))
-            rb04 : kp < key
-            rb04 = lt
-            rb16 : color n1 ≡ Black
-            rb16 = proj1 (RBtreeChildrenColorBlack _ _ (subst (λ k → RBtreeInvariant k) x rb09) (trans (cong color (sym x)) pcolor))
-            rb13 : ⟪ Red , proj2 vp ⟫ ≡ vp
-            rb13 with subst (λ k → color k ≡ Red ) x pcolor
-            ... | refl = refl
-            rb14 : ⟪ Black , proj2 vg ⟫ ≡ vg
-            rb14 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02) (case2 pcolor)
-            ... | refl = refl
-            rb33 : color (PG.grand pg) ≡ Black
-            rb33 = subst (λ k → color k ≡ Black ) (sym x₁) (sym (cong proj1 rb14))
-            rb03 : replacedRBTree key value (node kg _ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ))
-                (node kp ⟪ Black , proj2 vp ⟫  (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) n1 ) repl )
-            rb03 = rbr-rotate-rr repl-red rb04 rot
-            rb10 : node kp ⟪ Black , proj2 vp ⟫ (node kg ⟪ Red , proj2 vg ⟫ (PG.uncle pg) n1 ) repl ≡ rb01
-            rb10 = cong (λ  k → node _ _  _ k ) (sym eq)
-            rb12 : node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r)) ≡ PG.grand pg
-            rb12 = begin
-                 node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r)) 
-                       ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k n1 (RBI.tree r) ) ) rb14 rb13 ⟩
-                 node kg vg (PG.uncle pg) _ ≡⟨ cong (λ k → node _ _ _ k) (sym x) ⟩
-                 node kg vg (PG.uncle pg) (PG.parent pg) ≡⟨ sym x₁ ⟩
-                 PG.grand pg ∎ where open ≡-Reasoning
-            rb11 : replacedRBTree key value (PG.grand pg) rb01
-            rb11 = subst₂ (λ j k → replacedRBTree key value j k) rb12 rb10 rb03
-            rb05 : RBtreeInvariant (PG.uncle pg)
-            rb05 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb02)
-            rb06 : RBtreeInvariant n1
-            rb06 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb09)
-            rb19 : black-depth (PG.uncle pg) ≡ black-depth n1 
-            rb19 = sym (trans (sym ( proj1 (red-children-eq x (sym (cong proj1 rb13))  rb09) )) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb02))))
-            rb18 : black-depth (PG.uncle pg) ⊔ black-depth n1 ≡ black-depth repl  
-            rb18 = sym ( begin
-               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-               black-depth (RBI.tree r) ≡⟨ sym ( RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb09)) ⟩
-               black-depth n1 ≡⟨ sym (⊔-idem (black-depth n1)) ⟩
-               black-depth n1 ⊔ black-depth n1 ≡⟨ cong (λ k → k ⊔ _) (sym rb19) ⟩
-               black-depth (PG.uncle pg) ⊔ black-depth n1 ∎ ) where open ≡-Reasoning
-                -- suc (black-depth (node rkey vr rp-left rp-right) ⊔ (black-depth n1 ⊔ black-depth (PG.uncle pg))) ≡ black-depth (PG.grand pg)
-            rb17 : suc (black-depth (PG.uncle pg) ⊔ black-depth n1 ⊔ black-depth (node rkey vr rp-left rp-right)) ≡ black-depth (PG.grand pg)
-            rb17 = begin 
-                suc (black-depth (PG.uncle pg) ⊔ black-depth n1 ⊔ black-depth (node rkey vr rp-left rp-right)) 
-                      ≡⟨ cong₂ (λ j k → suc (j ⊔ black-depth k)) rb18 eq  ⟩
-                suc (black-depth repl ⊔ black-depth repl) ≡⟨ ⊔-idem _ ⟩
-                suc (black-depth repl ) ≡⟨ cong suc (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
-                suc (black-depth (RBI.tree r) ) ≡⟨ cong suc (sym (proj2 (red-children-eq x (cong proj1 (sym rb13)) rb09))) ⟩
-                suc (black-depth (PG.parent pg) ) ≡⟨ sym (proj2 (black-children-eq refl (cong proj1 (sym rb14)) (subst (λ k → RBtreeInvariant k) x₁ rb02))) ⟩
-                black-depth (node kg vg (PG.uncle pg) (PG.parent pg)) ≡⟨ cong black-depth (sym x₁) ⟩
-                black-depth (PG.grand pg) ∎ where open ≡-Reasoning
-    replaceRBP1 : t
-    replaceRBP1 with RBI.state r
-    ... | rebuild ceq bdepth-eq ¬leaf rot = rebuildCase ceq bdepth-eq ¬leaf rot
-    ... | top-black eq rot = exit stack (trans eq (cong (λ k → k ∷ []) rb00)) r where
-        rb00 : RBI.tree r ≡ orig
-        rb00 with si-property-last _ _ _ _ (subst (λ k → stackInvariant key (RBI.tree r) orig k) (eq) (RBI.si r))
-        ... | refl = refl
-    ... | rotate _ repl-red rot with stackToPG (RBI.tree r) orig stack (RBI.si r)
-    ... | case1 eq  = exit stack eq r     -- no stack, replace top node
-    ... | case2 (case1 eq) = insertCase4 orig refl eq rot (case1 repl-red) (RBI.si r)     -- one level stack, orig is parent of repl
-    ... | case2 (case2 pg) with color (PG.parent pg) in pcolor
-    ... | Black = insertCase1 where
-       -- Parent is Black, make color repl ≡ color tree then goto rebuildCase
-       rb00 : (pg : PG (Color ∧ A) key (RBI.tree r) stack) → stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-       rb00 pg = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-       treerb : (pg : PG (Color ∧ A) key (RBI.tree r) stack) → RBtreeInvariant (PG.parent pg)
-       treerb pg = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (rb00 pg))
-       rb08 : (pg : PG (Color ∧ A) key (RBI.tree r) stack) → treeInvariant (PG.parent pg)
-       rb08 pg = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ (rb00 pg))
-       insertCase1 : t
-       insertCase1 with PG.pg pg
-       ... | s2-s1p2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.parent pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = treerb pg
-            ; replrb = rb06
-            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
-                (subst (λ k → replacedRBTree key value k (node kp vp repl n1) ) (sym x) (rb02 rb04 ))
-           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-            rb01 : bt (Color ∧ A)
-            rb01 = node kp vp repl n1
-            rb03 : key < kp
-            rb03 = lt
-            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
-            rb04 with subst (λ k → color k ≡ Black) x pcolor
-            ... | refl = refl
-            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp (RBI.tree r) n1) (node kp vp repl n1)
-            rb02 eq = subst (λ k → replacedRBTree key value (node kp k (RBI.tree r) n1) (node kp k repl n1)) eq (rbr-black-left repl-red rb03 rot )
-            rb07 : black-depth repl ≡ black-depth n1
-            rb07 = begin
-               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-               black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)) ⟩
-               black-depth n1 ∎
-                 where open ≡-Reasoning
-            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
-            rb05 refl = begin
-               suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong suc (cong (λ k → k ⊔ black-depth n1) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
-               suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ refl ⟩
-               black-depth (node kp vp (RBI.tree r) n1) ≡⟨ cong black-depth (sym x) ⟩
-               black-depth (PG.parent pg) ∎
-                 where open ≡-Reasoning
-            rb06 : RBtreeInvariant rb01
-            rb06 = subst (λ k → RBtreeInvariant (node kp k repl n1))  rb04
-               ( rb-black _ _ rb07 (RBI.replrb r) (RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))))
-       ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.parent pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = treerb pg
-            ; replrb = rb06
-            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
-                (subst (λ k → replacedRBTree key value k (node kp vp n1 repl) ) (sym x) (rb02 rb04 ))
-           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-               --- x  : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
-               --- x₁ : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
-            rb01 : bt (Color ∧ A)
-            rb01 = node kp vp n1 repl
-            rb03 : kp < key
-            rb03 = lt
-            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
-            rb04 with subst (λ k → color k ≡ Black) x pcolor
-            ... | refl = refl
-            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp n1 (RBI.tree r) ) (node kp vp n1 repl )
-            rb02 eq = subst (λ k → replacedRBTree key value (node kp k n1 (RBI.tree r) ) (node kp k n1 repl )) eq (rbr-black-right repl-red rb03 rot )
-            rb07 : black-depth repl ≡ black-depth n1
-            rb07 = begin
-               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-               black-depth (RBI.tree r) ≡⟨ sym ( RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg))) ⟩
-               black-depth n1 ∎
-                 where open ≡-Reasoning
-            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
-            rb05 refl = begin
-               suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong suc (cong (λ k → black-depth n1 ⊔ k ) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
-               suc (black-depth n1 ⊔ black-depth (RBI.tree r)) ≡⟨ refl ⟩
-               black-depth (node kp vp n1 (RBI.tree r) ) ≡⟨ cong black-depth (sym x) ⟩
-               black-depth (PG.parent pg) ∎
-                 where open ≡-Reasoning
-            rb06 : RBtreeInvariant rb01
-            rb06 = subst (λ k → RBtreeInvariant (node kp k n1 repl ))  rb04
-               ( rb-black _ _ (sym rb07) (RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))) (RBI.replrb r) )
-       insertCase1 | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.parent pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = treerb pg
-            ; replrb = rb06
-            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
-                (subst (λ k → replacedRBTree key value k (node kp vp repl n1) ) (sym x) (rb02 rb04 ))
-           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-            rb01 : bt (Color ∧ A)
-            rb01 = node kp vp repl n1
-            rb03 : key < kp
-            rb03 = lt
-            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
-            rb04 with subst (λ k → color k ≡ Black) x pcolor
-            ... | refl = refl
-            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp (RBI.tree r) n1) (node kp vp repl n1)
-            rb02 eq = subst (λ k → replacedRBTree key value (node kp k (RBI.tree r) n1) (node kp k repl n1)) eq (rbr-black-left repl-red rb03 rot )
-            rb07 : black-depth repl ≡ black-depth n1
-            rb07 = begin
-               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-               black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg)) ⟩
-               black-depth n1 ∎
-                 where open ≡-Reasoning
-            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
-            rb05 refl = begin
-               suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong suc (cong (λ k → k ⊔ black-depth n1) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
-               suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ refl ⟩
-               black-depth (node kp vp (RBI.tree r) n1) ≡⟨ cong black-depth (sym x) ⟩
-               black-depth (PG.parent pg) ∎
-                 where open ≡-Reasoning
-            rb06 : RBtreeInvariant rb01
-            rb06 = subst (λ k → RBtreeInvariant (node kp k repl n1))  rb04
-               ( rb-black _ _ rb07 (RBI.replrb r) (RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))))
-       insertCase1 | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = next (PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) record {
-            tree = PG.parent pg
-            ; repl = rb01
-            ; origti = RBI.origti r
-            ; origrb = RBI.origrb r
-            ; treerb = treerb pg
-            ; replrb = rb06
-            ; si = popStackInvariant _ _ _ _ _ (rb00 pg)
-            ; state = rebuild (cong color x)  (rb05 (trans (sym (cong color x)) pcolor)) (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ()))
-                (subst (λ k → replacedRBTree key value k (node kp vp n1 repl) ) (sym x) (rb02 rb04 ))
-           } (subst₂ (λ j k → j < length k ) refl (sym (PG.stack=gp pg)) ≤-refl) where
-                -- x   : PG.parent pg ≡ node kp vp (RBI.tree r) n1
-                -- x₁  : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
-            rb01 : bt (Color ∧ A)
-            rb01 = node kp vp n1 repl
-            rb03 : kp < key
-            rb03 = lt
-            rb04 :  ⟪ Black , proj2 vp ⟫ ≡ vp
-            rb04 with subst (λ k → color k ≡ Black) x pcolor
-            ... | refl = refl
-            rb02 : ⟪ Black , proj2 vp ⟫ ≡ vp → replacedRBTree key value (node kp vp n1 (RBI.tree r) ) (node kp vp n1 repl )
-            rb02 eq = subst (λ k → replacedRBTree key value (node kp k n1 (RBI.tree r) ) (node kp k n1 repl )) eq (rbr-black-right repl-red rb03 rot )
-            rb07 : black-depth repl ≡ black-depth n1
-            rb07 = begin
-               black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-               black-depth (RBI.tree r) ≡⟨ sym ( RBtreeEQ (subst (λ k → RBtreeInvariant k) x (treerb pg))) ⟩
-               black-depth n1 ∎
-                 where open ≡-Reasoning
-            rb05 : proj1 vp ≡ Black → black-depth rb01 ≡ black-depth (PG.parent pg)
-            rb05 refl = begin
-               suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong suc (cong (λ k → black-depth n1 ⊔ k ) (sym (RB-repl→eq _ _ (RBI.treerb r) rot))) ⟩
-               suc (black-depth n1 ⊔ black-depth (RBI.tree r)) ≡⟨ refl ⟩
-               black-depth (node kp vp n1 (RBI.tree r) ) ≡⟨ cong black-depth (sym x) ⟩
-               black-depth (PG.parent pg) ∎
-                 where open ≡-Reasoning
-            rb06 : RBtreeInvariant rb01
-            rb06 = subst (λ k → RBtreeInvariant (node kp k n1 repl ))  rb04
-               ( rb-black _ _ (sym rb07) (RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x (treerb pg))) (RBI.replrb r) )
-    ... | Red with PG.uncle pg in uneq
-    ... | leaf = insertCase5 repl refl pg rot repl-red (cong color uneq) pcolor
-    ... | node key₁ ⟪ Black , value₁ ⟫ t₁ t₂ = insertCase5 repl refl pg rot repl-red (cong color uneq) pcolor
-    ... | node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ with PG.pg pg   -- insertCase2 : uncle and parent are Red, flip color and go up by two level
-    ... | s2-s1p2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
-        insertCase2 : t
-        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
-            record {
-                 tree = PG.grand pg
-                 ; repl = to-red (node kg vg (to-black (node kp vp repl n1)) (to-black (PG.uncle pg)))
-                 ; origti = RBI.origti r
-                 ; origrb = RBI.origrb r
-                 ; treerb = rb01
-                 ; replrb = rb-red _ _ refl (RBtreeToBlackColor _ rb02) rb12 (rb-black _ _ rb13 (RBI.replrb r) rb04) (RBtreeToBlack _ rb02)
-                 ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) (sym rb09) refl  (rbr-flip-ll repl-red (rb05 refl uneq) rb06 rot))
-             }  rb15 where
-               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-               rb01 :  RBtreeInvariant (PG.grand pg)
-               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
-               rb02 : RBtreeInvariant (PG.uncle pg)
-               rb02 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb03 : RBtreeInvariant (PG.parent pg)
-               rb03 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb04 : RBtreeInvariant n1
-               rb04 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
-               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
-               rb05 refl refl = refl
-               rb08 : treeInvariant (PG.parent pg)
-               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
-               rb07 : treeInvariant (node kp vp (RBI.tree r) n1)
-               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
-               rb06 : key < kp
-               rb06 = lt
-               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
-               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case1 pcolor)
-               ... | refl = refl
-               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
-               rb11 with subst (λ k → color k ≡ Red) x pcolor
-               ... | refl = refl
-               rb09 : PG.grand pg ≡ node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) (PG.uncle pg)
-               rb09 = begin
-                   PG.grand pg ≡⟨ x₁ ⟩
-                   node kg vg (PG.parent pg) (PG.uncle pg) ≡⟨ cong (λ k → node kg vg k (PG.uncle pg)) x ⟩
-                   node kg vg (node kp vp (RBI.tree r) n1) (PG.uncle pg) ≡⟨ cong₂ (λ j k → node kg j (node kp k (RBI.tree r) n1) (PG.uncle pg)) rb10 rb11  ⟩
-                   node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) (PG.uncle pg) ∎
-                     where open ≡-Reasoning
-               rb13 : black-depth repl ≡ black-depth n1
-               rb13 = begin
-                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                  black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03) ⟩
-                  black-depth n1 ∎
-                     where open ≡-Reasoning
-               rb12 : suc (black-depth repl ⊔ black-depth n1) ≡ black-depth (to-black (PG.uncle pg))
-               rb12 = begin
-                  suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
-                  suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
-                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
-                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj2 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
-                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01)) ⟩
-                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
-                  black-depth (to-black (PG.uncle pg)) ∎
-                     where open ≡-Reasoning
-               rb15 : suc (length (PG.rest pg)) < length stack
-               rb15 = begin
-                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
-                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
-                  length stack ∎
-                     where open ≤-Reasoning
-    ... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
-        insertCase2 : t
-        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
-            record {
-                 tree = PG.grand pg
-                 ; repl = to-red (node kg vg (to-black (node kp vp n1 repl)) (to-black (PG.uncle pg))  )
-                 ; origti = RBI.origti r
-                 ; origrb = RBI.origrb r
-                 ; treerb = rb01
-                 ; replrb = rb-red _ _ refl (RBtreeToBlackColor _ rb02) rb12 (rb-black _ _ (sym rb13) rb04 (RBI.replrb r)) (RBtreeToBlack _ rb02)
-                  ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) rb09 refl (rbr-flip-lr repl-red (rb05 refl uneq) rb06 rb21 rot))
-             }  rb15 where
-               --
-               -- lt       : kp < key
-               --  x       : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
-               --- x₁      : PG.grand pg ≡ node kg vg (PG.parent pg) (PG.uncle pg)
-               --
-               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-               rb01 : RBtreeInvariant (PG.grand pg)
-               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
-               rb02 : RBtreeInvariant (PG.uncle pg)
-               rb02 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb03 : RBtreeInvariant (PG.parent pg)
-               rb03 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb04 : RBtreeInvariant n1
-               rb04 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
-               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
-               rb05 refl refl = refl
-               rb08 : treeInvariant (PG.parent pg)
-               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
-               rb07 : treeInvariant (node kp vp n1 (RBI.tree r) )
-               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
-               rb06 : kp < key
-               rb06 = lt
-               rb21 : key < kg   -- this can be a part of ParentGand relation
-               rb21 = si-property-< (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r) 
-                     (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)))) 
-                     (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
-               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
-               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case1 pcolor)
-               ... | refl = refl
-               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
-               rb11 with subst (λ k → color k ≡ Red) x pcolor
-               ... | refl = refl 
-               rb09 : node kg ⟪ Black , proj2 vg ⟫  (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ) (PG.uncle pg) ≡ PG.grand pg
-               rb09 = sym ( begin
-                   PG.grand pg ≡⟨ x₁ ⟩
-                   node kg vg  (PG.parent pg) (PG.uncle pg) ≡⟨ cong (λ k → node kg vg k (PG.uncle pg)) x ⟩
-                   node kg vg  (node kp vp n1 (RBI.tree r) ) (PG.uncle pg)  ≡⟨ cong₂ (λ j k → node kg j  (node kp k n1 (RBI.tree r) ) (PG.uncle pg) ) rb10 rb11  ⟩
-                   node kg ⟪ Black , proj2 vg ⟫ (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ) (PG.uncle pg) ∎ )
-                     where open ≡-Reasoning
-               rb13 : black-depth repl ≡ black-depth n1
-               rb13 = begin
-                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                  black-depth (RBI.tree r) ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
-                  black-depth n1 ∎
-                     where open ≡-Reasoning
-               rb12 : suc (black-depth n1 ⊔ black-depth repl) ≡ black-depth (to-black (PG.uncle pg))
-               rb12 = begin
-                  suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong (λ k → suc (black-depth n1 ⊔ k)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
-                  suc (black-depth n1 ⊔ black-depth (RBI.tree r)) ≡⟨ cong (λ k → suc (black-depth n1 ⊔ k)) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03))) ⟩
-                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
-                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj1 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
-                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01)) ⟩
-                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
-                  black-depth (to-black (PG.uncle pg)) ∎
-                     where open ≡-Reasoning
-               rb15 : suc (length (PG.rest pg)) < length stack
-               rb15 = begin
-                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
-                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
-                  length stack ∎
-                     where open ≤-Reasoning
-    ... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
-        insertCase2 : t
-        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
-            record {
-                 tree = PG.grand pg
-                 ; repl = to-red (node kg vg (to-black (PG.uncle pg)) (to-black (node kp vp repl n1)) )
-                 ; origti = RBI.origti r
-                 ; origrb = RBI.origrb r
-                 ; treerb = rb01
-                 ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-                 ; replrb = rb-red _ _ (RBtreeToBlackColor _ rb02) refl rb12 (RBtreeToBlack _ rb02) (rb-black _ _ rb13 (RBI.replrb r) rb04) 
-                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) rb09 refl  (rbr-flip-rl repl-red (rb05 refl uneq) rb21 rb06 rot))
-             }  rb15 where
-                 -- x   : PG.parent pg ≡ node kp vp (RBI.tree r) n1
-                 -- x₁  : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
-               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-               rb01 :  RBtreeInvariant (PG.grand pg)
-               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
-               rb02 : RBtreeInvariant (PG.uncle pg)
-               rb02 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb03 : RBtreeInvariant (PG.parent pg)
-               rb03 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb04 : RBtreeInvariant n1
-               rb04 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
-               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
-               rb05 refl refl = refl
-               rb08 : treeInvariant (PG.parent pg)
-               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
-               rb07 : treeInvariant (node kp vp (RBI.tree r) n1)
-               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
-               rb06 : key < kp
-               rb06 = lt
-               rb21 : kg < key   -- this can be a part of ParentGand relation
-               rb21 = si-property-> (subst (λ k → ¬ (k ≡ leaf)) (sym x) (λ ())) (subst (λ k → treeInvariant k ) x₁ (siToTreeinvariant _ _ _ _ (RBI.origti r) 
-                     (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)))) 
-                     (subst (λ k → stackInvariant key _ orig (PG.parent pg ∷ k ∷ PG.rest pg)) x₁ (popStackInvariant _ _ _ _ _ rb00))
-               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
-               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case2 pcolor)
-               ... | refl = refl
-               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
-               rb11 with subst (λ k → color k ≡ Red) x pcolor
-               ... | refl = refl
-               rb09 : node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) ≡ PG.grand pg
-               rb09 = sym ( begin
-                   PG.grand pg ≡⟨ x₁ ⟩
-                   node kg vg (PG.uncle pg) (PG.parent pg)  ≡⟨ cong (λ k → node kg vg (PG.uncle pg) k) x ⟩
-                   node kg vg (PG.uncle pg) (node kp vp (RBI.tree r) n1)  ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k (RBI.tree r) n1) ) rb10 rb11  ⟩
-                   node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ (RBI.tree r) n1) ∎ )
-                     where open ≡-Reasoning
-               rb13 : black-depth repl ≡ black-depth n1
-               rb13 = begin
-                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                  black-depth (RBI.tree r) ≡⟨ RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03) ⟩
-                  black-depth n1 ∎
-                     where open ≡-Reasoning
-               -- rb12 : suc (black-depth repl ⊔ black-depth n1) ≡ black-depth (to-black (PG.uncle pg))
-               rb12 : black-depth (to-black (PG.uncle pg)) ≡ suc (black-depth repl ⊔ black-depth n1)
-               rb12 = sym ( begin
-                  suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
-                  suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
-                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
-                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj2 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
-                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01))) ⟩
-                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
-                  black-depth (to-black (PG.uncle pg)) ∎ )
-                     where open ≡-Reasoning
-               rb17 : suc (black-depth repl ⊔ black-depth n1) ⊔ black-depth (to-black (PG.uncle pg)) ≡ black-depth (PG.grand pg)
-               rb17 = begin
-                  suc (black-depth repl ⊔ black-depth n1) ⊔ black-depth (to-black (PG.uncle pg)) ≡⟨ cong (λ k → k ⊔ black-depth (to-black (PG.uncle pg))) (sym rb12) ⟩
-                  black-depth (to-black (PG.uncle pg)) ⊔ black-depth (to-black (PG.uncle pg)) ≡⟨ ⊔-idem _ ⟩
-                  black-depth (to-black (PG.uncle pg)) ≡⟨ sym (to-black-eq (PG.uncle pg) (cong color uneq )) ⟩
-                  suc (black-depth (PG.uncle pg)) ≡⟨ sym ( proj1 (black-children-eq x₁ (cong proj1 rb10) rb01 )) ⟩
-                  black-depth (PG.grand pg) ∎
-                     where open ≡-Reasoning
-               rb15 : suc (length (PG.rest pg)) < length stack
-               rb15 = begin
-                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
-                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
-                  length stack ∎
-                     where open ≤-Reasoning
-    ... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} lt x x₁ = insertCase2 where
-           --- lt : kp < key
-           --- x  : PG.parent pg ≡ node kp vp n1 (RBI.tree r)
-           --- x₁ : PG.grand pg ≡ node kg vg (PG.uncle pg) (PG.parent pg)
-        insertCase2 : t
-        insertCase2 = next  (PG.grand pg ∷ (PG.rest pg))
-            record {
-                 tree = PG.grand pg
-                 ; repl = to-red (node kg vg (to-black (PG.uncle pg)) (to-black (node kp vp n1 repl )) )
-                 ; origti = RBI.origti r
-                 ; origrb = RBI.origrb r
-                 ; treerb = rb01
-                 ; replrb = rb-red _ _ (RBtreeToBlackColor _ rb02) refl rb12  (RBtreeToBlack _ rb02) (rb-black _ _ (sym rb13) rb04 (RBI.replrb r) )
-                 ; si = popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00)
-                 ; state = rotate _ refl (subst₂ (λ j k → replacedRBTree key value j k ) (sym rb09) refl  (rbr-flip-rr repl-red (rb05 refl uneq) rb06 rot))
-             }  rb15 where
-               rb00 : stackInvariant key (RBI.tree r) orig (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg)
-               rb00 = subst (λ k → stackInvariant key (RBI.tree r) orig k) (PG.stack=gp pg) (RBI.si r)
-               rb01 :  RBtreeInvariant (PG.grand pg)
-               rb01 = PGtoRBinvariant1 _ orig (RBI.origrb r) _ (popStackInvariant _ _ _ _ _ (popStackInvariant _ _ _ _ _ rb00))
-               rb02 : RBtreeInvariant (PG.uncle pg)
-               rb02 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb03 : RBtreeInvariant (PG.parent pg)
-               rb03 = RBtreeRightDown _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01)
-               rb04 : RBtreeInvariant n1
-               rb04 = RBtreeLeftDown _ _ (subst (λ k → RBtreeInvariant k) x rb03)
-               rb05 : { tree : bt (Color ∧ A) } → tree ≡ PG.uncle pg → tree ≡ node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ → color (PG.uncle pg) ≡ Red
-               rb05 refl refl = refl
-               rb08 : treeInvariant (PG.parent pg)
-               rb08 = siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00)
-               rb07 : treeInvariant (node kp vp n1 (RBI.tree r) )
-               rb07 = subst (λ k → treeInvariant k) x (siToTreeinvariant _ _ _ _ (RBI.origti r) (popStackInvariant _ _ _ _ _ rb00))
-               rb06 : kp < key
-               rb06 = lt
-               rb10 : vg ≡ ⟪ Black , proj2 vg ⟫
-               rb10 with RBtreeParentColorBlack _ _ (subst (λ k → RBtreeInvariant k) x₁ rb01) (case2 pcolor)
-               ... | refl = refl
-               rb11 : vp ≡ ⟪ Red , proj2 vp ⟫
-               rb11 with subst (λ k → color k ≡ Red) x pcolor
-               ... | refl = refl
-               rb09 : PG.grand pg ≡ node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) ) 
-               rb09 = begin
-                   PG.grand pg ≡⟨ x₁ ⟩
-                   node kg vg (PG.uncle pg) (PG.parent pg) ≡⟨ cong (λ k → node kg vg (PG.uncle pg) k) x ⟩
-                   node kg vg (PG.uncle pg) (node kp vp n1 (RBI.tree r) )  ≡⟨ cong₂ (λ j k → node kg j (PG.uncle pg) (node kp k n1 (RBI.tree r) ) ) rb10 rb11  ⟩
-                   node kg ⟪ Black , proj2 vg ⟫ (PG.uncle pg) (node kp ⟪ Red , proj2 vp ⟫ n1 (RBI.tree r) )  ∎
-                     where open ≡-Reasoning
-               rb13 : black-depth repl ≡ black-depth n1
-               rb13 = begin
-                  black-depth repl ≡⟨ sym (RB-repl→eq _ _ (RBI.treerb r) rot) ⟩
-                  black-depth (RBI.tree r) ≡⟨ sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03)) ⟩
-                  black-depth n1 ∎
-                     where open ≡-Reasoning
-               rb12 : black-depth (to-black (PG.uncle pg)) ≡ suc (black-depth n1 ⊔ black-depth repl)
-               rb12 = sym ( begin
-                  suc (black-depth n1 ⊔ black-depth repl) ≡⟨ cong suc (⊔-comm (black-depth n1) _) ⟩
-                  suc (black-depth repl ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RB-repl→eq _ _ (RBI.treerb r) rot)) ⟩
-                  suc (black-depth (RBI.tree r) ⊔ black-depth n1) ≡⟨ cong (λ k → suc (k ⊔ black-depth n1)) (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x rb03))) ⟩
-                  suc (black-depth n1 ⊔ black-depth n1) ≡⟨ ⊔-idem _ ⟩
-                  suc (black-depth n1 ) ≡⟨ cong suc (sym (proj1 (red-children-eq x (cong proj1 rb11) rb03 ))) ⟩
-                  suc (black-depth (PG.parent pg)) ≡⟨ cong suc (sym (RBtreeEQ (subst (λ k → RBtreeInvariant k) x₁ rb01))) ⟩
-                  suc (black-depth (PG.uncle pg)) ≡⟨ to-black-eq (PG.uncle pg) (cong color uneq ) ⟩
-                  black-depth (to-black (PG.uncle pg)) ∎ )
-                     where open ≡-Reasoning
-               rb15 : suc (length (PG.rest pg)) < length stack
-               rb15 = begin
-                  suc (suc (length (PG.rest pg))) ≤⟨ <-trans (n<1+n _) (n<1+n _) ⟩
-                  length (RBI.tree r ∷ PG.parent pg ∷ PG.grand pg ∷ PG.rest pg) ≡⟨ cong length (sym (PG.stack=gp pg)) ⟩
-                  length stack ∎
-                     where open ≤-Reasoning
-
-