- parallel substitution reaxiomatized

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / etc / fsup / fsups.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc/fsup/fsups.etc b/matita/matita/contribs/lambdadelta/basic_2/etc/fsup/fsups.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/grammar/fsupp.ma".
+
+(* STAR-ITERATED SUPCLOSURE *************************************************)
+
+definition fsups: bi_relation lenv term ≝ bi_star … fsup.
+
+interpretation "star-iterated structural successor (closure)"
+   'SupTermStar L1 T1 L2 T2 = (fsups L1 T1 L2 T2).
+
+(* Basic eliminators ********************************************************)
+
+lemma fsups_ind: ∀L1,T1. ∀R:relation2 lenv term. R L1 T1 →
+                 (∀L,L2,T,T2. ⦃L1, T1⦄ ⊃* ⦃L, T⦄ → ⦃L, T⦄ ⊃ ⦃L2, T2⦄ → R L T → R L2 T2) →
+                 ∀L2,T2. ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄ → R L2 T2.
+#L1 #T1 #R #IH1 #IH2 #L2 #T2 #H
+@(bi_star_ind … IH1 IH2 ? ? H)
+qed-.
+
+lemma fsups_ind_dx: ∀L2,T2. ∀R:relation2 lenv term. R L2 T2 →
+                    (∀L1,L,T1,T. ⦃L1, T1⦄ ⊃ ⦃L, T⦄ → ⦃L, T⦄ ⊃* ⦃L2, T2⦄ → R L T → R L1 T1) →
+                    ∀L1,T1. ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄ → R L1 T1.
+#L2 #T2 #R #IH1 #IH2 #L1 #T1 #H
+@(bi_star_ind_dx … IH1 IH2 ? ? H)
+qed-.
+
+(* Basic properties *********************************************************)
+
+lemma fsups_refl: bi_reflexive … fsups.
+/2 width=1/ qed.
+
+lemma fsupp_fsups: ∀L1,L2,T1,T2. ⦃L1, T1⦄ ⊃+ ⦃L2, T2⦄ → ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄.
+/2 width=1/ qed.
+
+lemma fsup_fsups: ∀L1,L2,T1,T2. ⦃L1, T1⦄ ⊃ ⦃L2, T2⦄ → ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄.
+/2 width=1/ qed.
+
+lemma fsups_strap1: ∀L1,L,L2,T1,T,T2. ⦃L1, T1⦄ ⊃* ⦃L, T⦄ → ⦃L, T⦄ ⊃ ⦃L2, T2⦄ →
+                    ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄.
+/2 width=4/ qed.
+
+lemma fsups_strap2: ∀L1,L,L2,T1,T,T2. ⦃L1, T1⦄ ⊃ ⦃L, T⦄ → ⦃L, T⦄ ⊃* ⦃L2, T2⦄ →
+                    ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄.
+/2 width=4/ qed.
+
+lemma fsups_fsupp_fsupp: ∀L1,L,L2,T1,T,T2. ⦃L1, T1⦄ ⊃* ⦃L, T⦄ →
+                         ⦃L, T⦄ ⊃+ ⦃L2, T2⦄ → ⦃L1, T1⦄ ⊃+ ⦃L2, T2⦄.
+/2 width=4/ qed.
+
+lemma fsupp_fsups_fsupp: ∀L1,L,L2,T1,T,T2. ⦃L1, T1⦄ ⊃+ ⦃L, T⦄ →
+                         ⦃L, T⦄ ⊃* ⦃L2, T2⦄ → ⦃L1, T1⦄ ⊃+ ⦃L2, T2⦄.
+/2 width=4/ qed.
+
+(* Basic forward lemmas *****************************************************)
+
+lemma fsups_fwd_cw: ∀L1,L2,T1,T2. ⦃L1, T1⦄ ⊃* ⦃L2, T2⦄ → ♯{L2, T2} ≤ ♯{L1, T1}.
+#L1 #L2 #T1 #T2 #H @(fsups_ind … H) -L2 -T2 //
+/4 width=3 by fsup_fwd_cw, lt_to_le_to_lt, lt_to_le/ (**) (* slow even with trace *)
+qed-.
+
+(* Advanced inversion lemmas on plus-iterated supclosure ********************)
+
+lemma fsupp_inv_bind1_fsups: ∀b,J,L1,L2,W,U,T2. ⦃L1, ⓑ{b,J}W.U⦄ ⊃+ ⦃L2, T2⦄ →
+                             ⦃L1, W⦄ ⊃* ⦃L2, T2⦄ ∨ ⦃L1.ⓑ{J}W, U⦄ ⊃* ⦃L2, T2⦄.
+#b #J #L1 #L2 #W #U #T2 #H @(fsupp_ind … H) -L2 -T2
+[ #L2 #T2 #H
+  elim (fsup_inv_bind1 … H) -H * #H1 #H2 destruct /2 width=1/
+| #L #T #L2 #T2 #_ #HT2 * /3 width=4/
+]
+qed-.
+
+lemma fsupp_inv_flat1_fsups: ∀J,L1,L2,W,U,T2. ⦃L1, ⓕ{J}W.U⦄ ⊃+ ⦃L2, T2⦄ →
+                             ⦃L1, W⦄ ⊃* ⦃L2, T2⦄ ∨ ⦃L1, U⦄ ⊃* ⦃L2, T2⦄.
+#J #L1 #L2 #W #U #T2 #H @(fsupp_ind … H) -L2 -T2
+[ #L2 #T2 #H
+  elim (fsup_inv_flat1 … H) -H #H1 * #H2 destruct /2 width=1/
+| #L #T #L2 #T2 #_ #HT2 * /3 width=4/
+]
+qed-.