matita/matita/contribs/lambdadelta/basic_2A/etc/cny/cpye_cpye.etc

   1 (**************************************************************************)
   2 (*       ___                                                              *)
   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
   6 (*      ||I||       Developers:                                           *)
   7 (*      ||T||         The HELM team.                                      *)
   8 (*      ||A||         http://helm.cs.unibo.it                             *)
   9 (*      \   /                                                             *)
  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
  12 (*                                                                        *)
  13 (**************************************************************************)
  14
  15 include "basic_2/substitution/cpys_cny.ma".
  16 include "basic_2/substitution/cpys_cpys.ma".
  17 include "basic_2/substitution/cpye.ma".
  18
  19 (* EVALUATION FOR CONTEXT-SENSITIVE EXTENDED SUBSTITUTION ON TERMS **********)
  20
  21 (* Advanced properties ******************************************************)
  22
  23 lemma cpye_cpys_conf: ∀G,L,T,T2,d,e. ⦃G, L⦄ ⊢ T ▶*[d, e] 𝐍⦃T2⦄ →
  24                       ∀T1. ⦃G, L⦄ ⊢ T ▶*[d, e] T1 → ⦃G, L⦄ ⊢ T1 ▶*[d, e] T2.
  25 #G #L #T #T2 #d #e * #H2 #HT2 #T1 #H1 elim (cpys_conf_eq … H1 … H2) -T
  26 #T0 #HT10 #HT20 >(cpys_inv_cny1 … HT2 … HT20) -T2 //
  27 qed-.
  28