matita/matita/contribs/lambda_delta/basic_2/equivalence/lsubse_ssta.ma

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  14
  15 (*
  16 include "basic_2/computation/xprs_lsubss.ma".
  17 *)
  18 include "basic_2/equivalence/lsubse.ma".
  19
  20 (* LOCAL ENVIRONMENT REFINEMENT FOR CONTEXT-SENSITIVE PARALLEL EQUIVALENCE **)
  21
  22 (* Properties on stratified native type assignment **************************)
  23
  24 axiom lsubse_ssta_trans: ∀h,g,L2,T,U2,l. ⦃h, L2⦄ ⊢ T •[g,l] U2 →
  25                          ∀L1. h ⊢ L1 ⊢•⊑[g] L2 →
  26                          ∃∃U1. ⦃h, L1⦄ ⊢ T •[g,l] U1 & L1 ⊢ U1 ⬌* U2.