milestone update in ground_2 and basic_2A

[helm.git] / matita / matita / contribs / lambdadelta / basic_2A / etc / cny / cpye_alt.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2A/etc/cny/cpye_alt.etc b/matita/matita/contribs/lambdadelta/basic_2A/etc/cny/cpye_alt.etc
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||M||                                                             *)
+(*      ||A||       A project by Andrea Asperti                           *)
+(*      ||T||                                                             *)
+(*      ||I||       Developers:                                           *)
+(*      ||T||         The HELM team.                                      *)
+(*      ||A||         http://helm.cs.unibo.it                             *)
+(*      \   /                                                             *)
+(*       \ /        This file is distributed under the terms of the       *)
+(*        v         GNU General Public License Version 2                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+include "basic_2/notation/relations/psubstevalalt_6.ma".
+include "basic_2/substitution/cpye_lift.ma".
+
+(* EVALUATION FOR CONTEXT-SENSITIVE EXTENDED SUBSTITUTION ON TERMS **********)
+
+(* Note: alternative definition of cpye *)
+inductive cpyea: ynat → ynat → relation4 genv lenv term term ≝
+| cpyea_sort : ∀G,L,d,e,k. cpyea d e G L (⋆k) (⋆k)
+| cpyea_free : ∀G,L,d,e,i. |L| ≤ i → cpyea d e G L (#i) (#i)
+| cpyea_top  : ∀G,L,d,e,i. d + e ≤ yinj i → cpyea d e G L (#i) (#i)
+| cpyea_skip : ∀G,L,d,e,i. yinj i < d → cpyea d e G L (#i) (#i)
+| cpyea_subst: ∀I,G,L,K,V1,V2,W2,i,d,e. d ≤ yinj i → yinj i < d+e →
+               ⇩[i] L ≡ K.ⓑ{I}V1 → cpyea (yinj 0) (⫰(d+e-yinj i)) G K V1 V2 →
+               ⇧[0, i+1] V2 ≡ W2 → cpyea d e G L (#i) W2
+| cpyea_gref : ∀G,L,d,e,p. cpyea d e G L (§p) (§p)
+| cpyea_bind : ∀a,I,G,L,V1,V2,T1,T2,d,e.
+               cpyea d e G L V1 V2 → cpyea (⫯d) e G (L.ⓑ{I}V1) T1 T2 →
+               cpyea d e G L (ⓑ{a,I}V1.T1) (ⓑ{a,I}V2.T2)
+| cpyea_flat : ∀I,G,L,V1,V2,T1,T2,d,e.
+               cpyea d e G L V1 V2 → cpyea d e G L T1 T2 →
+               cpyea d e G L (ⓕ{I}V1.T1) (ⓕ{I}V2.T2)
+.
+
+interpretation
+   "evaluation for context-sensitive extended substitution (term) alternative"
+   'PSubstEvalAlt G L T1 T2 d e = (cpyea d e G L T1 T2).
+
+(* Main properties **********************************************************)
+
+theorem cpye_cpyea: ∀G,L,T1,T2,d,e. ⦃G, L⦄ ⊢ T1 ▶*[d, e] 𝐍⦃T2⦄ → ⦃G, L⦄ ⊢ T1 ▶▶*[d, e] 𝐍⦃T2⦄.
+#G #L #T1 @(fqup_wf_ind_eq … G L T1) -G -L -T1
+#Z #Y #X #IH #G #L * *
+[ #k #_ #_ #_ #T2 #d #e #H -X -Y -Z >(cpye_inv_sort1 … H) -H //
+| #i #HG #HL #HT #T2 #d #e #H destruct
+  elim (cpye_inv_lref1 … H) -H *
+  /4 width=7 by cpyea_subst, cpyea_free, cpyea_top, cpyea_skip, fqup_lref/
+| #p #_ #_ #_ #T2 #d #e #H -X -Y -Z >(cpye_inv_gref1 … H) -H //
+| #a #I #V1 #T1 #HG #HL #HT #T #d #e #H destruct
+  elim (cpye_inv_bind1 … H) -H /3 width=1 by cpyea_bind/
+| #I #V1 #T1 #HG #HL #HT #T #d #e #H destruct
+  elim (cpye_inv_flat1 … H) -H /3 width=1 by cpyea_flat/
+]
+qed.
+
+(* Main inversion properties ************************************************)
+
+theorem cpyea_inv_cpye: ∀G,L,T1,T2,d,e. ⦃G, L⦄ ⊢ T1 ▶▶*[d, e] 𝐍⦃T2⦄ → ⦃G, L⦄ ⊢ T1 ▶*[d, e] 𝐍⦃T2⦄.
+#G #L #T1 #T2 #d #e #H elim H -G -L -T1 -T2 -d -e
+/2 width=7 by cpye_subst, cpye_flat, cpye_bind, cpye_skip, cpye_top, cpye_free/
+qed-.
+
+(* Advanced eliminators *****************************************************)
+
+lemma cpye_ind_alt: ∀R:ynat→ynat→relation4 genv lenv term term.
+                    (∀G,L,d,e,k. R d e G L (⋆k) (⋆k)) →
+                    (∀G,L,d,e,i. |L| ≤ i → R d e G L (#i) (#i)) →
+                    (∀G,L,d,e,i. d + e ≤ yinj i → R d e G L (#i) (#i)) →
+                    (∀G,L,d,e,i. yinj i < d → R d e G L (#i) (#i)) →
+                    (∀I,G,L,K,V1,V2,W2,i,d,e. d ≤ yinj i → yinj i < d + e →
+                     ⇩[i] L ≡ K.ⓑ{I}V1 → ⦃G, K⦄ ⊢ V1 ▶*[yinj O, ⫰(d+e-yinj i)] 𝐍⦃V2⦄ →
+                     ⇧[O, i+1] V2 ≡ W2 → R (yinj O) (⫰(d+e-yinj i)) G K V1 V2 → R d e G L (#i) W2
+                    ) →
+                    (∀G,L,d,e,p. R d e G L (§p) (§p)) →
+                    (∀a,I,G,L,V1,V2,T1,T2,d,e. ⦃G, L⦄ ⊢ V1 ▶*[d, e] 𝐍⦃V2⦄ →
+                     ⦃G, L.ⓑ{I}V1⦄ ⊢ T1 ▶*[⫯d, e] 𝐍⦃T2⦄ → R d e G L V1 V2 →
+                     R (⫯d) e G (L.ⓑ{I}V1) T1 T2 → R d e G L (ⓑ{a,I}V1.T1) (ⓑ{a,I}V2.T2)
+                    ) →
+                    (∀I,G,L,V1,V2,T1,T2,d,e. ⦃G, L⦄ ⊢ V1 ▶*[d, e] 𝐍⦃V2⦄ →
+                     ⦃G, L⦄ ⊢ T1 ▶*[d, e] 𝐍⦃T2⦄ → R d e G L V1 V2 →
+                     R d e G L T1 T2 → R d e G L (ⓕ{I}V1.T1) (ⓕ{I}V2.T2)
+                    ) →
+                    ∀d,e,G,L,T1,T2. ⦃G, L⦄ ⊢ T1 ▶*[d, e] 𝐍⦃T2⦄ → R d e G L T1 T2.
+#R #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #d #e #G #L #T1 #T2 #H elim (cpye_cpyea … H) -G -L -T1 -T2 -d -e
+/3 width=8 by cpyea_inv_cpye/
+qed-.