update in lambdadelta

[helm.git] / matita / matita / contribs / lambdadelta / basic_2A / unfold / unfold.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2A/unfold/unfold.ma b/matita/matita/contribs/lambdadelta/basic_2A/unfold/unfold.ma
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+++ b/matita/matita/contribs/lambdadelta/basic_2A/unfold/unfold.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_2A/notation/relations/unfold_4.ma".
+include "basic_2A/grammar/lenv_append.ma".
+include "basic_2A/grammar/genv.ma".
+include "basic_2A/substitution/drop.ma".
+
+(* CONTEXT-SENSITIVE UNFOLD FOR TERMS ***************************************)
+
+(* activate genv *)
+inductive unfold: relation4 genv lenv term lenv ≝
+| unfold_sort: ∀G,L,k. unfold G L (⋆k) L
+| unfold_lref: ∀I,G,L1,L2,K1,K2,V,i. ⬇[i] L1 ≡ K1. ⓑ{I}V →
+               unfold G K1 V K2 → ⬇[Ⓣ, |L2|, i] L2 ≡ K2 →
+               unfold G L1 (#i) (L1@@L2)
+| unfold_bind: ∀a,I,G,L1,L2,V,T.
+               unfold G (L1.ⓑ{I}V) T L2 → unfold G L1 (ⓑ{a,I}V.T) L2
+| unfold_flat: ∀I,G,L1,L2,V,T.
+               unfold G L1 T L2 → unfold G L1 (ⓕ{I}V.T) L2
+.
+
+interpretation "context-sensitive unfold (term)"
+   'Unfold G L1 T L2 = (unfold G L1 T L2).