matita/matita/contribs/lambdadelta/basic_2/etc_2A1/cpr/cpr_ltpss_dx.etc

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  14
  15 include "basic_2/unfold/ltpss_dx_ltpss_dx.ma".
  16 include "basic_2/reducibility/cpr.ma".
  17
  18 (* CONTEXT-SENSITIVE PARALLEL REDUCTION ON TERMS ****************************)
  19
  20 (* Properties concerning dx partial unfold on local environments ************)
  21
  22 lemma ltpss_dx_cpr_conf: ∀L1,T,U1. L1 ⊢ T ➡ U1 →
  23                          ∀L2,d,e. L1 ▶* [d, e] L2 →
  24                          ∃∃U2. L2 ⊢ T ➡ U2 & L2 ⊢ U1 ▶* [d, e] U2.
  25 #L1 #T #U1 * #U #HTU #HU1 #L2 #d #e #HL12
  26 lapply (ltpss_dx_fwd_length … HL12) #H >H in HU1; -H #HU1
  27 elim (ltpss_dx_tpss_conf … HU1 … HL12) -L1 /3 width=3/
  28 qed-.