--- /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 "apps_2/models/model_props.ma".
+
+(* EVALUATION EQUIVALENCE **************************************************)
+
+definition veq (M): relation (evaluation M) ≝
+ λv1,v2. ∀d. v1 d ≗ v2 d.
+
+interpretation "evaluation equivalence (model)"
+ 'RingEq M v1 v2 = (veq M v1 v2).
+
+(* Basic properties *********************************************************)
+
+lemma veq_refl (M): is_model M →
+ reflexive … (veq M).
+/2 width=1 by mq/ qed.
+(*
+lemma veq_sym: ∀M. symmetric … (veq M).
+// qed-.
+
+theorem veq_trans: ∀M. transitive … (veq M).
+// qed-.
+*)
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