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1 open import Level hiding ( suc ; zero )
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2 open import Algebra
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3 module Gutil {n m : Level} (G : Group n m ) where
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5 open import Data.Unit
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6 open import Function.Inverse as Inverse using (_↔_; Inverse; _InverseOf_)
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7 open import Function
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8 open import Data.Nat hiding (_⊔_) -- using (ℕ; suc; zero)
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9 open import Relation.Nullary
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10 open import Data.Empty
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11 open import Data.Product
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12 open import Relation.Binary.PropositionalEquality hiding ( [_] )
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15 open Group G
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16
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17 import Relation.Binary.Reasoning.Setoid as EqReasoning
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18
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19 gsym = Algebra.Group.sym G
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20 grefl = Algebra.Group.refl G
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21 gtrans = Algebra.Group.trans G
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22
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23 lemma3 : ε ≈ ε ⁻¹
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24 lemma3 = begin
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25 ε ≈⟨ gsym (proj₁ inverse _) ⟩
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26 ε ⁻¹ ∙ ε ≈⟨ proj₂ identity _ ⟩
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27 ε ⁻¹
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28 ∎ where open EqReasoning (Algebra.Group.setoid G)
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29
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30 lemma6 : {f : Carrier } → ( f ⁻¹ ) ⁻¹ ≈ f
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31 lemma6 {f} = begin
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32 ( f ⁻¹ ) ⁻¹ ≈⟨ gsym ( proj₁ identity _) ⟩
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33 ε ∙ ( f ⁻¹ ) ⁻¹ ≈⟨ ∙-cong (gsym ( proj₂ inverse _ )) grefl ⟩
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34 (f ∙ f ⁻¹ ) ∙ ( f ⁻¹ ) ⁻¹ ≈⟨ assoc _ _ _ ⟩
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35 f ∙ ( f ⁻¹ ∙ ( f ⁻¹ ) ⁻¹ ) ≈⟨ ∙-cong grefl (proj₂ inverse _) ⟩
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36 f ∙ ε ≈⟨ proj₂ identity _ ⟩
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37 f
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38 ∎ where open EqReasoning (Algebra.Group.setoid G)
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39
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40 ≡→≈ : {f g : Carrier } → f ≡ g → f ≈ g
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41 ≡→≈ refl = grefl
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42
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43 ---
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44 -- to avoid assoc storm, flatten multiplication according to the template
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45 --
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46
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47 data MP : Carrier → Set (Level.suc n) where
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48 am : (x : Carrier ) → MP x
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49 _o_ : {x y : Carrier } → MP x → MP y → MP ( x ∙ y )
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50
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51 mpf : {x : Carrier } → (m : MP x ) → Carrier → Carrier
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52 mpf (am x) y = x ∙ y
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53 mpf (m o m₁) y = mpf m ( mpf m₁ y )
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54
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55 mp-flatten : {x : Carrier } → (m : MP x ) → Carrier
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56 mp-flatten m = mpf m ε
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57
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58 mpl1 : Carrier → {x : Carrier } → MP x → Carrier
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59 mpl1 x (am y) = x ∙ y
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60 mpl1 x (y o y1) = mpl1 ( mpl1 x y ) y1
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61
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62 mpl : {x z : Carrier } → MP x → MP z → Carrier
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63 mpl (am x) m = mpl1 x m
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64 mpl (m o m1) m2 = mpl m (m1 o m2)
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65
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66 mp-flattenl : {x : Carrier } → (m : MP x ) → Carrier
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67 mp-flattenl m = mpl m (am ε)
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68
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69 test1 : ( f g : Carrier ) → Carrier
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70 test1 f g = mp-flattenl ((am (g ⁻¹) o am (f ⁻¹) ) o ( (am f o am g) o am ((f ∙ g) ⁻¹ )))
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71
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72 test2 : ( f g : Carrier ) → test1 f g ≡ g ⁻¹ ∙ f ⁻¹ ∙ f ∙ g ∙ (f ∙ g) ⁻¹ ∙ ε
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73 test2 f g = _≡_.refl
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74
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75 test3 : ( f g : Carrier ) → Carrier
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76 test3 f g = mp-flatten ((am (g ⁻¹) o am (f ⁻¹) ) o ( (am f o am g) o am ((f ∙ g) ⁻¹ )))
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77
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78 test4 : ( f g : Carrier ) → test3 f g ≡ g ⁻¹ ∙ (f ⁻¹ ∙ (f ∙ (g ∙ ((f ∙ g) ⁻¹ ∙ ε))))
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79 test4 f g = _≡_.refl
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80
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81
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82 ∙-flatten : {x : Carrier } → (m : MP x ) → x ≈ mp-flatten m
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83 ∙-flatten {x} (am x) = gsym (proj₂ identity _)
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84 ∙-flatten {_} (am x o q) = ∙-cong grefl ( ∙-flatten q )
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85 ∙-flatten (_o_ {_} {z} (_o_ {x} {y} p q) r) = lemma9 _ _ _ ( ∙-flatten {x ∙ y } (p o q )) ( ∙-flatten {z} r ) where
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86 mp-cong : {p q r : Carrier} → (P : MP p) → q ≈ r → mpf P q ≈ mpf P r
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87 mp-cong (am x) q=r = ∙-cong grefl q=r
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88 mp-cong (P o P₁) q=r = mp-cong P ( mp-cong P₁ q=r )
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89 mp-assoc : {p q r : Carrier} → (P : MP p) → mpf P q ∙ r ≈ mpf P (q ∙ r )
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90 mp-assoc (am x) = assoc _ _ _
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91 mp-assoc {p} {q} {r} (P o P₁) = begin
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92 mpf P (mpf P₁ q) ∙ r ≈⟨ mp-assoc P ⟩
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93 mpf P (mpf P₁ q ∙ r) ≈⟨ mp-cong P (mp-assoc P₁) ⟩ mpf P ((mpf P₁) (q ∙ r))
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94 ∎ where open EqReasoning (Algebra.Group.setoid G)
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95 lemma9 : (x y z : Carrier) → x ∙ y ≈ mpf p (mpf q ε) → z ≈ mpf r ε → x ∙ y ∙ z ≈ mp-flatten ((p o q) o r)
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96 lemma9 x y z t s = begin
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97 x ∙ y ∙ z ≈⟨ ∙-cong t grefl ⟩
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98 mpf p (mpf q ε) ∙ z ≈⟨ mp-assoc p ⟩
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99 mpf p (mpf q ε ∙ z) ≈⟨ mp-cong p (mp-assoc q ) ⟩
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100 mpf p (mpf q (ε ∙ z)) ≈⟨ mp-cong p (mp-cong q (proj₁ identity _ )) ⟩
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101 mpf p (mpf q z) ≈⟨ mp-cong p (mp-cong q s) ⟩
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102 mpf p (mpf q (mpf r ε))
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103 ∎ where open EqReasoning (Algebra.Group.setoid G)
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104
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105 grepl : { x y0 y1 z : Carrier } → x ∙ y0 ≈ y1 → x ∙ ( y0 ∙ z ) ≈ y1 ∙ z
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106 grepl eq = gtrans (gsym (assoc _ _ _ )) (∙-cong eq grefl )
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107
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108 grm : { x y0 y1 z : Carrier } → x ∙ y0 ≈ ε → x ∙ ( y0 ∙ z ) ≈ z
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109 grm eq = gtrans ( gtrans (gsym (assoc _ _ _ )) (∙-cong eq grefl )) ( proj₁ identity _ )
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110
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111 -- ∙-flattenl : {x : Carrier } → (m : MP x ) → x ≈ mp-flattenl m
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112 -- ∙-flattenl (am x) = gsym (proj₂ identity _)
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113 -- ∙-flattenl (q o am x) with ∙-flattenl q -- x₁ ∙ x ≈ mpl q (am x o am ε) , t : x₁ ≈ mpl q (am ε)
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114 -- ... | t = {!!}
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115 -- ∙-flattenl (q o (x o y )) with ∙-flattenl q
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116 -- ... | t = gtrans (gsym (assoc _ _ _ )) {!!}
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117
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118 lemma5 : (f g : Carrier ) → g ⁻¹ ∙ f ⁻¹ ≈ (f ∙ g) ⁻¹
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119 lemma5 f g = begin
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120 g ⁻¹ ∙ f ⁻¹ ≈⟨ gsym (proj₂ identity _) ⟩
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121 g ⁻¹ ∙ f ⁻¹ ∙ ε ≈⟨ gsym (∙-cong grefl (proj₂ inverse _ )) ⟩
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122 g ⁻¹ ∙ f ⁻¹ ∙ ( (f ∙ g) ∙ (f ∙ g) ⁻¹ ) ≈⟨ ∙-flatten ((am (g ⁻¹) o am (f ⁻¹) ) o ( (am f o am g) o am ((f ∙ g) ⁻¹ ))) ⟩
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123 g ⁻¹ ∙ (f ⁻¹ ∙ (f ∙ (g ∙ ((f ∙ g) ⁻¹ ∙ ε)))) ≈⟨ ∙-cong grefl (gsym (assoc _ _ _ )) ⟩
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124 g ⁻¹ ∙ ((f ⁻¹ ∙ f) ∙ (g ∙ ((f ∙ g) ⁻¹ ∙ ε))) ≈⟨ ∙-cong grefl (gtrans (∙-cong (proj₁ inverse _ ) grefl) (proj₁ identity _)) ⟩
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125 g ⁻¹ ∙ (g ∙ ((f ∙ g) ⁻¹ ∙ ε)) ≈⟨ gsym (assoc _ _ _) ⟩
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126 (g ⁻¹ ∙ g ) ∙ ((f ∙ g) ⁻¹ ∙ ε) ≈⟨ gtrans (∙-cong (proj₁ inverse _ ) grefl) (proj₁ identity _) ⟩
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127 (f ∙ g) ⁻¹ ∙ ε ≈⟨ proj₂ identity _ ⟩
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128 (f ∙ g) ⁻¹
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129 ∎ where open EqReasoning (Algebra.Group.setoid G)
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130
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