update in static_2 and basic_2

[helm.git] / matita / matita / contribs / lambdadelta / static_2 / syntax / tweq_simple.ma

diff --git a/matita/matita/contribs/lambdadelta/static_2/syntax/tweq_simple.ma b/matita/matita/contribs/lambdadelta/static_2/syntax/tweq_simple.ma
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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 "static_2/syntax/term_simple.ma".
+include "static_2/syntax/tweq.ma".
+
+(* SORT-IRRELEVANT WHD EQUIVALENCE ON TERMS *********************************)
+
+(* Properties with simple terms *********************************************)
+
+lemma tweq_simple_trans:
+      ∀T1,T2. T1 ≅ T2 → 𝐒⦃T1⦄ → 𝐒⦃T2⦄.
+#T1 #T2 * -T1 -T2
+[4,5: #p #V1 #V2 #T1 #T2 [ #_ ] #H
+      elim (simple_inv_bind … H)
+|*  : /1 width=1 by simple_atom, simple_flat/
+]
+qed-.