matita/matita/contribs/lambda_delta/basic_2/computation/cprs_delift.ma

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  14
  15 include "basic_2/reducibility/cpr_delift.ma".
  16 include "basic_2/computation/cprs.ma".
  17
  18 (* CONTEXT-SENSITIVE PARALLEL COMPUTATION ON TERMS **************************)
  19
  20 (* Properties on inverse basic term relocation ******************************)
  21
  22 (* Basic_1: was only: pr3_gen_cabbr *)
  23 lemma thin_cprs_delift_conf: ∀L,U1,U2. L ⊢ U1 ➡* U2 →
  24                              ∀K,d,e. L ▼*[d, e] ≡ K → ∀T1. L ⊢ U1 ▼*[d, e] ≡ T1 →
  25                              ∃∃T2. K ⊢ T1 ➡* T2 & L ⊢ U2 ▼*[d, e] ≡ T2.
  26 #L #U1 #U2 #H @(cprs_ind … H) -U2 /2 width=3/
  27 #U #U2 #_ #HU2 #IHU1 #K #d #e #HLK #T1 #HTU1
  28 elim (IHU1 … HLK … HTU1) -U1 #T #HT1 #HUT
  29 elim (thin_cpr_delift_conf … HU2 … HLK … HUT) -U -HLK /3 width=3/
  30 qed.