The two coercions sym_eq e eq_f gives BIG TROUBLES when checking composition during

qed. In particular, checking composition calls unification, that calls reductions,
that is problematic when there are a lot of lein in the context (as is it the case
with proofs generated by TPTP: see eg GRP486-1.p.ma )

diff --git a/matita/library/logic/equality.ma b/matita/library/logic/equality.ma
index 0561fb993cb90045a502a12dcf28a14680f46fdb..3b242c66709d6562debbc465a00e930cd4fb370e 100644 (file)
--- 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.