matita/matita/contribs/lambdadelta/basic_2/etc/delift/tpr_delift.etc

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  14
  15 include "basic_2/unfold/delift.ma".
  16 include "basic_2/reducibility/ltpr_tpss.ma".
  17
  18 (* CONTEXT-FREE PARALLEL REDUCTION ON TERMS *********************************)
  19
  20 (* Properties on inverse basic term relocation ******************************)
  21
  22 lemma tpr_delift_conf: ∀U1,U2. U1 ➡ U2 → ∀L,T1,d,e. L ⊢ ▼*[d, e] U1 ≡ T1 →
  23                        ∃∃T2. T1 ➡ T2 & L ⊢ ▼*[d, e] U2 ≡ T2.
  24 #U1 #U2 #HU12 #L #T1 #d #e * #W1 #HUW1 #HTW1
  25 elim (tpr_tpss_conf … HU12 … HUW1) -U1 #U1 #HWU1 #HU21
  26 elim (tpr_inv_lift1 … HWU1 … HTW1) -W1 /3 width=5/
  27 qed-.