X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=matita%2Flibrary%2Flogic%2Fequality.ma;h=3b242c66709d6562debbc465a00e930cd4fb370e;hb=fae6f153d6dad76b6ccfce17a6b3d997db338d2e;hp=0561fb993cb90045a502a12dcf28a14680f46fdb;hpb=e53c9d7cf1a5d3d33c41cad5b046b018a62a9d2d;p=helm.git

diff --git a/matita/library/logic/equality.ma b/matita/library/logic/equality.ma
index 0561fb993..3b242c667 100644
--- a/matita/library/logic/equality.ma
+++ b/matita/library/logic/equality.ma
@@ -65,8 +65,15 @@ theorem eq_f: \forall  A,B:Type.\forall f:A\to B.
 intros.elim H.apply refl_eq.
 qed.
 
+theorem eq_f': \forall  A,B:Type.\forall f:A\to B.
+\forall x,y:A. x=y \to f y = f x.
+intros.elim H.apply refl_eq.
+qed.
+
+(* 
 coercion cic:/matita/logic/equality/sym_eq.con.
 coercion cic:/matita/logic/equality/eq_f.con.
+*)
 
 default "equality"
  cic:/matita/logic/equality/eq.ind
@@ -75,7 +82,7 @@ default "equality"
  cic:/matita/logic/equality/eq_ind.con
  cic:/matita/logic/equality/eq_elim_r.con
  cic:/matita/logic/equality/eq_f.con
- cic:/matita/logic/equality/eq_OF_eq.con. (* \x.sym (eq_f x) *)
+ cic:/matita/logic/equality/eq_f'.con. (* \x.sym (eq_f x) *)
  
 theorem eq_f2: \forall  A,B,C:Type.\forall f:A\to B \to C.
 \forall x1,x2:A. \forall y1,y2:B.