matita/matita/contribs/lambdadelta/apps_2/etc/models/vdrop_vlift.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 "apps_2/models/model_vlift.ma".
  16 include "apps_2/models/vdrop.ma".
  17
  18 (* EVALUATION DROP **********************************************************)
  19
  20 (* Advanced properties with evaluation evaluation lift **********************)
  21
  22 lemma vlift_vdrop_eq (M): ∀lv,i. lv ≐{?,dd M} ⫯[i←lv i]⫰[i]lv.
  23 #M #lv #i #j elim (lt_or_eq_or_gt j i) #Hji destruct
  24 [ >vlift_lt // >vdrop_lt //
  25 | >vlift_eq //
  26 | >vlift_gt // >vdrop_ge /2 width=1 by monotonic_pred/
  27   <(lt_succ_pred … Hji) //
  28 ]
  29 qed.