--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+set "baseuri" "cic:/matita/test/".
+
+include "nat/nat.ma".
+
+axiom A : Type.
+
+inductive vec : nat -> Type :=
+ | vnil : vec O
+ | vcons : ∀x:A.∀n:nat. vec n -> vec (S n).
+
+definition f := λx,n.λv:vec n.vcons x n v.
+definition g := λn,x.λv:vec n.vcons x n v.
+
+include "logic/equality.ma".
+
+(* definition xx := f = g. *)
+theorem xx1 : ∀n.∀x1:vec n.f ? ? x1 = g ? ? x1.