diff yoneda.agda @ 253:24e83b8b81be

fix
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Wed, 11 Sep 2013 20:26:48 +0900
parents b2874c5086ea
children 8c72f5284bc8
line wrap: on
line diff
--- a/yoneda.agda	Mon Sep 09 16:15:09 2013 +0900
+++ b/yoneda.agda	Wed Sep 11 20:26:48 2013 +0900
@@ -305,13 +305,14 @@
 --     YondaLemma2 : {a b x : Obj A }  → (FObj (FObj YonedaFunctor a) x)  ≡ (FObj (FObj YonedaFunctor b  ) x)  →     
 --         a ≡ b 
 --     YondaLemma2 {a} {b} eq  = {!!}
+--       N.B     = ≡-cong gives you ! a ≡ b, so we cannot cong inv to prove a ≡ b
 --
--- Instead we prove 
+-- Instead we prove only
 --     inv ( FObj YonedaFunctor a )  ≡ a
 
 inv :  {a x : Obj A} ( f : FObj (FObj YonedaFunctor a) x)  →  Obj A
 inv {a} f =  Category.cod A f
 
-YonedaLemma21 :  (a x : Obj A) { f : ( FObj (FObj YonedaFunctor a) x) } →  inv f  ≡ a
-YonedaLemma21 a x {f} = refl
+YonedaLemma21 :  {a x : Obj A} ( f : ( FObj (FObj YonedaFunctor a) x) ) →  inv f  ≡ a
+YonedaLemma21 {a} {x} f = refl