matita/matita/contribs/lambdadelta/basic_2/relocation/ldrop_lsuby.ma

   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/relocation/lsuby_lsuby.ma".
  16 include "basic_2/relocation/ldrop.ma".
  17
  18 (* BASIC SLICING FOR LOCAL ENVIRONMENTS *************************************)
  19
  20 (* Properties on local environment refinement for extended substitution *****)
  21
  22 lemma dedropable_sn_TC: ∀R. dedropable_sn R → dedropable_sn (TC … R).
  23 #R #HR #L1 #K1 #s #d #e #HLK1 #K2 #H elim H -K2
  24 [ #K2 #HK12 elim (HR … HLK1 … HK12) -HR -K1
  25   /3 width=4 by inj, ex3_intro/
  26 | #K #K2 #_ #HK2 * #L #H1L1 #HLK #H2L1 elim (HR … HLK … HK2) -HR -K
  27   /3 width=6 by lsuby_trans, step, ex3_intro/
  28 ]
  29 qed-.