- degree-based equivalene for terms

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / etc_2A1 / cpr / cpcs_ltpss_sn.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/cpr/cpcs_ltpss_sn.etc b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/cpr/cpcs_ltpss_sn.etc
new file mode 100644 (file)
index 0000000..5bf1ed5
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/cpr/cpcs_ltpss_sn.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/equivalence/cpcs_ltpss_dx.ma".
+
+(* CONTEXT-SENSITIVE PARALLEL EQUIVALENCE ON TERMS **************************)
+
+(* Properties concerning sn partial unfold on local environments ************)
+
+lemma cpcs_ltpss_sn_conf: ∀L1,L2,d,e. L1 ⊢ ▶* [d, e] L2 →
+                          ∀T1,T2. L1 ⊢ T1 ⬌* T2 → L2 ⊢ T1 ⬌* T2.
+#L1 #L2 #d #e #H
+lapply (ltpss_sn_ltpssa … H) -H #H @(ltpssa_ind … H) -L2 //
+#L #L2 #_ #HL2 #IHL1 #T1 #U1 #HTU1
+lapply (IHL1 … HTU1) -IHL1 -HTU1 #HTU1
+lapply (cpcs_ltpss_dx_conf … HL2 … HTU1) -HTU1 -HL2 //
+qed-.