- degree-based equivalene for terms

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / etc_2A1 / delift / cpcs_delift.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/delift/cpcs_delift.etc b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/delift/cpcs_delift.etc
new file mode 100644 (file)
index 0000000..7012ec1
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+++ b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/delift/cpcs_delift.etc
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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 "basic_2/unfold/delift_lift.ma".
+include "basic_2/unfold/delift_delift.ma".
+include "basic_2/computation/cprs_delift.ma".
+include "basic_2/equivalence/cpcs_cpcs.ma".
+
+(* CONTEXT-SENSITIVE PARALLEL EQUIVALENCE ON TERMS **************************)
+
+(* Properties on inverse basic term relocation ******************************)
+
+lemma cpcs_zeta_delift_comm: ∀L,V,T1,T2. L.ⓓV ⊢ ▼*[O, 1] T1 ≡ T2 →
+                             L ⊢ T2 ⬌* +ⓓV.T1.
+/3 width=1/ qed.
+
+(* Basic_1: was only: pc3_gen_cabbr *)
+lemma thin_cpcs_delift_mono: ∀L,U1,U2. L ⊢ U1 ⬌* U2 →
+                             ∀K,d,e. ▼*[d, e] L ≡ K → ∀T1. L ⊢ ▼*[d, e] U1 ≡ T1 →
+                             ∀T2. L ⊢ ▼*[d, e] U2 ≡ T2 → K ⊢ T1 ⬌* T2.
+#L #U1 #U2 #H #K #d #e #HLK #T1 #HTU1 #T2 #HTU2
+elim (cpcs_inv_cprs … H) -H #U #HU1 #HU2
+elim (thin_cprs_delift_conf … HU1 … HLK … HTU1) -U1 #T #HT1 #HUT
+elim (thin_cprs_delift_conf … HU2 … HLK … HTU2) -U2 -HLK #X #HT2 #H
+lapply (delift_mono … H … HUT) -L #H destruct /2 width=3/
+qed.