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

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / rt_transition / cnx_basic.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/rt_transition/cnx_basic.ma b/matita/matita/contribs/lambdadelta/basic_2/rt_transition/cnx_basic.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 "static_2/relocation/lifts_tdeq.ma".
+include "basic_2/rt_transition/cpx_drops_basic.ma".
+include "basic_2/rt_transition/cnx.ma".
+
+(* NORMAL TERMS FOR UNBOUND CONTEXT-SENSITIVE PARALLEL RT-TRANSITION ********)
+
+(* Advanced inversion lemmas ************************************************)
+
+lemma cnx_inv_abbr_pos (h) (G) (L): ∀V,T.  ⦃G,L⦄ ⊢ ⬈[h] 𝐍⦃+ⓓV.T⦄ → ⊥.
+#h #G #L #V #U1 #H
+elim (cpx_subst h G (L.ⓓV) U1 … 0) [|*: /2 width=4 by drops_refl/ ] #U2 #T2 #HU12 #HTU2
+elim (tdeq_dec U1 U2) #HnU12 [ -HU12 | -HTU2 ]
+[ elim (tdeq_inv_lifts_dx … HnU12 … HTU2) -U2 #T1 #HTU1 #_ -T2
+  lapply (H T1 ?) -H [ /2 width=3 by cpx_zeta/ ] #H
+  /2 width=9 by tdeq_lifts_inv_pair_sn/
+| lapply (H (+ⓓV.U2) ?) -H [ /2 width=1 by cpx_bind/ ] -HU12 #H
+  elim (tdeq_inv_pair … H) -H #_ #_ /2 width=1 by/
+]
+qed-.