--- /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 *)
+(* *)
+(**************************************************************************)
+
+include "basics/relations.ma".
+
+(* GENERATED LIBRARY ********************************************************)
+
+lemma insert_eq_1 (T1) (a1) (Q1,Q2:predicate T1):
+ (∀b1. Q1 b1 → a1 = b1 → Q2 b1) → Q1 a1 → Q2 a1.
+/2 width=1 by/ qed-.