milestone in basic_2

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

diff --git a/matita/matita/contribs/lambdadelta/static_2/syntax/tweq_tdeq.ma b/matita/matita/contribs/lambdadelta/static_2/syntax/tweq_tdeq.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/tdeq.ma".
+include "static_2/syntax/tweq.ma".
+
+(* SORT-IRRELEVANT WHD EQUIVALENCE ON TERMS *********************************)
+
+(* Properties with sort-irrelevant equivalence for terms ********************)
+
+lemma tdeq_tweq: ∀T1,T2. T1 ≛ T2 → T1 ≅ T2.
+#T1 #T2 #H elim H -T1 -T2 [||| * [ #p ] * #V1 #V2 #T1 #T2 #_ #_ #IHV #IHT ]
+[ /1 width=1 by tweq_sort/
+| /1 width=1 by tweq_lref/
+| /1 width=1 by tweq_gref/
+| cases p -p /2 width=1 by tweq_abbr_pos, tweq_abbr_neg/  
+| /1 width=1 by tweq_abst/
+| /2 width=1 by tweq_appl/
+| /2 width=1 by tweq_cast/
+]
+qed.