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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
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15 include "basic_2/computation/lpxs_lleq.ma".
16 include "basic_2/computation/csx_alt.ma".
17 include "basic_2/computation/lsx.ma".
19 (* SN EXTENDED STRONGLY NORMALIZING LOCAL ENVIRONMENTS **********************)
21 (* Main properties **********************************************************)
23 axiom csx_lsx: ∀h,g,G,L,T. ⦃G, L⦄ ⊢ ⬊*[h, g] T → G ⊢ ⋕⬊*[h, g, T] L.
25 axiom lsx_inv_csx: ∀h,g,G,L,T. G ⊢ ⋕⬊*[h, g, T] L → ⦃G, L⦄ ⊢ ⬊*[h, g] T.
28 #h #g #G #L1 #T1 #H @(csx_ind_alt … H) -T1
29 #T1 #_ #IHT1 @lsx_intro
30 #L2 #HL12 #HnT1 elim (lpxs_inv_cpxs_nlleq … HL12 HnT1) -HL12 -HnT1
31 #T2 #H1T12 #HnT12 #H2T12 lapply (IHT1 … H1T12 HnT12) -IHT1 -H1T12 -HnT12