Merge branch 'matita-lablgtk3' of ssh://matita.cs.unibo.it:/srv/git/helm into matita...

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / rt_computation / cnuw.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/rt_computation/cnuw.ma b/matita/matita/contribs/lambdadelta/basic_2/rt_computation/cnuw.ma
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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/preditnormal_4.ma".
+include "static_2/syntax/tweq.ma".
+include "basic_2/rt_computation/cpms.ma".
+
+(* NORMAL TERMS FOR T-UNUNBOUND WHD RT-TRANSITION ***************************)
+
+definition cnuw (h) (G) (L): predicate term ≝
+           λT1. ∀n,T2. ⦃G,L⦄ ⊢ T1 ➡*[n,h] T2 → T1 ≅ T2.
+
+interpretation
+  "normality for t-unbound weak head context-sensitive parallel rt-transition (term)"
+  'PRedITNormal h G L T = (cnuw h G L T).
+
+(* Basic properties *********************************************************)
+
+lemma cnuw_sort (h) (G) (L): ∀s. ⦃G,L⦄ ⊢ ➡𝐍𝐖*[h] ⋆s.
+#h #G #L #s1 #n #X #H
+lapply (cpms_inv_sort1 … H) -H #H destruct //
+qed.
+
+lemma cnuw_ctop (h) (G): ∀i. ⦃G,⋆⦄ ⊢ ➡𝐍𝐖*[h] #i.
+#h #G #i #n #X #H
+elim (cpms_inv_lref1_ctop … H) -H #H #_ destruct //
+qed.
+
+lemma cnuw_zero_unit (h) (G) (L): ∀I. ⦃G,L.ⓤ{I}⦄ ⊢ ➡𝐍𝐖*[h] #0.
+#h #G #L #I #n #X #H
+elim (cpms_inv_zero1_unit … H) -H #H #_ destruct //
+qed.
+
+lemma cnuw_gref (h) (G) (L): ∀l. ⦃G,L⦄ ⊢ ➡𝐍𝐖*[h] §l.
+#h #G #L #l1 #n #X #H
+elim (cpms_inv_gref1 … H) -H #H #_ destruct //
+qed.
+
+(* Basic_inversion lemmas ***************************************************)
+
+lemma cnuw_inv_zero_pair (h) (I) (G) (L): ∀V. ⦃G,L.ⓑ{I}V⦄ ⊢ ➡𝐍𝐖*[h] #0 → ⊥.
+#h * #G #L #V #H
+elim (lifts_total V (𝐔❴1❵)) #W #HVW
+[ lapply (H 0 W ?) [ /3 width=3 by cpm_cpms, cpm_delta/ ]
+| lapply (H 1 W ?) [ /3 width=3 by cpm_cpms, cpm_ell/ ]
+] -H #HW
+lapply (tweq_inv_lref_sn … HW) -HW #H destruct
+/2 width=5 by lifts_inv_lref2_uni_lt/
+qed-.
+
+lemma cnuw_inv_cast (h) (G) (L):
+      ∀V,T. ⦃G,L⦄ ⊢ ➡𝐍𝐖*[h] ⓝV.T → ⊥.
+#h #G #L #V #T #H
+lapply (H 0 T ?) [ /3 width=1 by cpm_cpms, cpm_eps/ ] -H #H
+/2 width=3 by tweq_inv_cast_xy_y/
+qed-.
+
+(* Basic forward lemmas *****************************************************)
+
+lemma cnuw_fwd_appl (h) (G) (L):
+      ∀V,T. ⦃G,L⦄ ⊢ ➡𝐍𝐖*[h] ⓐV.T → ⦃G,L⦄ ⊢ ➡𝐍𝐖*[h] T.
+#h #G #L #V #T1 #HT1 #n #T2 #HT12
+lapply (HT1 n (ⓐV.T2) ?) -HT1
+/2 width=3 by cpms_appl_dx, tweq_inv_appl_bi/
+qed-.