matita/matita/contribs/lambdadelta/basic_2/rt_computation/cprs_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 "basic_2/rt_computation/cpms_drops.ma".
  16
  17 (* CONTEXT-SENSITIVE PARALLEL R-COMPUTATION FOR TERMS ***********************)
  18
  19 (* Advanced inversion lemmas ************************************************)
  20
  21 (* Basic_1: was: pr3_gen_lref *)
  22 (* Basic_2A1: was: cprs_inv_lref1 *)
  23 lemma cprs_inv_lref1_drops (h) (G): ∀L,T2,i. ❪G,L❫ ⊢ #i ➡*[h] T2 →
  24                                     ∨∨ T2 = #i
  25                                      | ∃∃K,V1,T1. ⇩*[i] L ≘ K.ⓓV1 & ❪G,K❫ ⊢ V1 ➡*[h] T1 &
  26                                                   ⇧*[↑i] T1 ≘ T2.
  27 #h #G #L #T2 #i #H elim (cpms_inv_lref1_drops … H) -H *
  28 [ /2 width=1 by or_introl/
  29 | /3 width=6 by ex3_3_intro, or_intror/
  30 | #m #K #V #V2 #_ #_ #_ #H destruct
  31 ]
  32 qed-.