- degree-based equivalene for terms

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

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/delift/delift_ltpss.etc b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/delift/delift_ltpss.etc
new file mode 100644 (file)
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+++ b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/delift/delift_ltpss.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/ltpss_sn_alt.ma".
+include "basic_2/unfold/delift.ma".
+
+(* INVERSE BASIC TERM RELOCATION  *******************************************)
+
+(* Properties on sn partial unfold on local environments ********************)
+
+lemma delift_ltpss_sn_conf_eq: ∀L,T1,T2,d,e. L ⊢ ▼*[d, e] T1 ≡ T2 →
+                               ∀K. L ⊢ ▶* [d, e] K → K ⊢ ▼*[d, e] T1 ≡ T2.
+#L #T1 #T2 #d #e * #T #HT1 #HT2 #K #HLK
+elim (ltpss_sn_tpss_conf … HT1 … HLK) -HT1 -HLK #T0 #HT10 #HT0
+lapply (tpss_inv_lift1_eq … HT0 … HT2) -HT0 #H destruct /2 width=3/
+qed.
+
+lemma ltpss_sn_delift_trans_eq: ∀L,K,d,e. L ⊢ ▶* [d, e] K →
+                                ∀T1,T2. K ⊢ ▼*[d, e] T1 ≡ T2 → L ⊢ ▼*[d, e] T1 ≡ T2.
+#L #K #d #e #HLK #T1 #T2 * #T #HT1 #HT2
+lapply (ltpss_sn_tpss_trans_eq … HT1 … HLK) -K /2 width=3/
+qed.