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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/notation/relations/lazysn_6.ma".
16 include "basic_2/substitution/lleq.ma".
17 include "basic_2/computation/lpxs.ma".
19 (* SN EXTENDED STRONGLY NORMALIZING LOCAL ENVIRONMENTS **********************)
21 definition lsx: ∀h. sd h → relation4 ynat term genv lenv ≝
22 λh,g,d,T,G. SN … (lpxs h g G) (lleq d T).
25 "extended strong normalization (local environment)"
26 'LazySN h g d T G L = (lsx h g T d G L).
28 (* Basic eliminators ********************************************************)
30 lemma lsx_ind: ∀h,g,G,T,d. ∀R:predicate lenv.
31 (∀L1. G ⊢ ⋕⬊*[h, g, T, d] L1 →
32 (∀L2. ⦃G, L1⦄ ⊢ ➡*[h, g] L2 → (L1 ⋕[T, d] L2 → ⊥) → R L2) →
35 ∀L. G ⊢ ⋕⬊*[h, g, T, d] L → R L.
36 #h #g #G #T #d #R #H0 #L1 #H elim H -L1
37 /5 width=1 by lleq_sym, SN_intro/
40 (* Basic properties *********************************************************)
42 lemma lsx_intro: ∀h,g,G,L1,T,d.
43 (∀L2. ⦃G, L1⦄ ⊢ ➡*[h, g] L2 → (L1 ⋕[T, d] L2 → ⊥) → G ⊢ ⋕⬊*[h, g, T, d] L2) →
44 G ⊢ ⋕⬊*[h, g, T, d] L1.
45 /5 width=1 by lleq_sym, SN_intro/ qed.
47 lemma lsx_atom: ∀h,g,G,T,d. G ⊢ ⋕⬊*[h, g, T, d] ⋆.
48 #h #g #G #T #d @lsx_intro
49 #X #H #HT lapply (lpxs_inv_atom1 … H) -H
50 #H destruct elim HT -HT //
53 lemma lsx_sort: ∀h,g,G,L,d,k. G ⊢ ⋕⬊*[h, g, ⋆k, d] L.
54 #h #g #G #L1 #d #k @lsx_intro
55 #L2 #HL12 #H elim H -H
56 /3 width=4 by lpxs_fwd_length, lleq_sort/
59 lemma lsx_gref: ∀h,g,G,L,d,p. G ⊢ ⋕⬊*[h, g, §p, d] L.
60 #h #g #G #L1 #d #p @lsx_intro
61 #L2 #HL12 #H elim H -H
62 /3 width=4 by lpxs_fwd_length, lleq_gref/
65 lemma lsx_be: ∀h,g,G,L,T,U,dt,d,e. yinj d ≤ dt → dt ≤ d + e →
66 ⇧[d, e] T ≡ U → G ⊢ ⋕⬊*[h, g, U, dt] L → G ⊢ ⋕⬊*[h, g, U, d] L.
67 #h #g #G #L #T #U #dt #d #e #Hddt #Hdtde #HTU #H @(lsx_ind … H) -L
68 /5 width=7 by lsx_intro, lleq_be/
71 (* Basic forward lemmas *****************************************************)
73 lemma lsx_fwd_bind_sn: ∀h,g,a,I,G,L,V,T,d. G ⊢ ⋕⬊*[h, g, ⓑ{a,I}V.T, d] L →
74 G ⊢ ⋕⬊*[h, g, V, d] L.
75 #h #g #a #I #G #L #V #T #d #H @(lsx_ind … H) -L
76 #L1 #_ #IHL1 @lsx_intro
77 #L2 #HL12 #HV @IHL1 /3 width=4 by lleq_fwd_bind_sn/
80 lemma lsx_fwd_flat_sn: ∀h,g,I,G,L,V,T,d. G ⊢ ⋕⬊*[h, g, ⓕ{I}V.T, d] L →
81 G ⊢ ⋕⬊*[h, g, V, d] L.
82 #h #g #I #G #L #V #T #d #H @(lsx_ind … H) -L
83 #L1 #_ #IHL1 @lsx_intro
84 #L2 #HL12 #HV @IHL1 /3 width=3 by lleq_fwd_flat_sn/
87 lemma lsx_fwd_flat_dx: ∀h,g,I,G,L,V,T,d. G ⊢ ⋕⬊*[h, g, ⓕ{I}V.T, d] L →
88 G ⊢ ⋕⬊*[h, g, T, d] L.
89 #h #g #I #G #L #V #T #d #H @(lsx_ind … H) -L
90 #L1 #_ #IHL1 @lsx_intro
91 #L2 #HL12 #HV @IHL1 /3 width=3 by lleq_fwd_flat_dx/
94 lemma lsx_fwd_pair_sn: ∀h,g,I,G,L,V,T,d. G ⊢ ⋕⬊*[h, g, ②{I}V.T, d] L →
95 G ⊢ ⋕⬊*[h, g, V, d] L.
96 #h #g * /2 width=4 by lsx_fwd_bind_sn, lsx_fwd_flat_sn/
99 (* Basic inversion lemmas ***************************************************)
101 lemma lsx_inv_flat: ∀h,g,I,G,L,V,T,d. G ⊢ ⋕⬊*[h, g, ⓕ{I}V.T, d] L →
102 G ⊢ ⋕⬊*[h, g, V, d] L ∧ G ⊢ ⋕⬊*[h, g, T, d] L.
103 /3 width=3 by lsx_fwd_flat_sn, lsx_fwd_flat_dx, conj/ qed-.