matita/matita/contribs/lambdadelta/basic_2A/multiple/drops_drops.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 "ground/relocation/mr2_append.ma".
  16 include "basic_2A/multiple/drops_drop.ma".
  17
  18 (* ITERATED LOCAL ENVIRONMENT SLICING ***************************************)
  19
  20 (* Main properties **********************************************************)
  21
  22 theorem drops_trans: ∀L,L2,s,cs2. ⬇*[s, cs2] L ≡ L2 → ∀L1,cs1. ⬇*[s, cs1] L1 ≡ L →
  23                      ⬇*[s, cs2 ;; cs1] L1 ≡ L2.
  24 #L #L2 #s #cs2 #H elim H -L -L2 -cs2 /3 width=3 by drops_cons/
  25 qed-.