matita/matita/contribs/lambdadelta/basic_2A/etc/llpx/llsx_ldrop.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/lleq_ldrop.ma".
  16 include "basic_2/computation/llsx.ma".
  17
  18 (* LAZY SN EXTENDED STRONGLY NORMALIZING LOCAL ENVIRONMENTS *****************)
  19
  20 (* Advanced properties ******************************************************)
  21
  22 lemma llsx_lref_free: ∀h,g,G,L,d,i. |L| ≤ i → G ⊢ ⋕⬊*[h, g, #i, d] L.
  23 #h #g #G #L1 #d #i #HL1 @llsx_intro
  24 #L2 #HL12 #H elim H -H
  25 /4 width=8 by llpx_fwd_length, lleq_free, le_repl_sn_conf_aux/
  26 qed.
  27
  28 lemma llsx_lref_skip: ∀h,g,G,L,d,i. yinj i < d → G ⊢ ⋕⬊*[h, g, #i, d] L.
  29 #h #g #G #L1 #d #i #HL1 @llsx_intro
  30 #L2 #HL12 #H elim H -H
  31 /3 width=6 by llpx_fwd_length, lleq_skip/
  32 qed.