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4 (* ||A|| A project by Andrea Asperti *)
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7 (* ||T|| The HELM team. *)
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16 include "basic_2/computation/xprs_lsubss.ma".
18 include "basic_2/equivalence/lsubse.ma".
20 (* LOCAL ENVIRONMENT REFINEMENT FOR CONTEXT-SENSITIVE PARALLEL EQUIVALENCE **)
22 (* Properties on stratified native type assignment **************************)
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.