X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambda_delta%2Fbasic_2%2Funfold%2Fthin.ma;fp=matita%2Fmatita%2Fcontribs%2Flambda_delta%2Fbasic_2%2Funfold%2Fthin.ma;h=0b4da98f9532e57c16a84e7125c70cbe22df7d0f;hb=913512bbc9202f2109d53acd43dc8c0270b17184;hp=0000000000000000000000000000000000000000;hpb=d1ee55ba423c73b08d9478e642a520a3e0057ed3;p=helm.git

diff --git a/matita/matita/contribs/lambda_delta/basic_2/unfold/thin.ma b/matita/matita/contribs/lambda_delta/basic_2/unfold/thin.ma
new file mode 100644
index 000000000..0b4da98f9
--- /dev/null
+++ b/matita/matita/contribs/lambda_delta/basic_2/unfold/thin.ma
@@ -0,0 +1,25 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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/unfold/ltpss.ma".
+
+(* DELIFT ON LOCAL ENVIRONMENTS  ********************************************)
+
+definition thin: nat → nat → relation lenv ≝
+                 λd,e,L1,L2. ∃∃L. L1 [d, e] ▶* L & ⇩[d, e] L ≡ L2.
+
+interpretation "delift (local environment)"
+   'TSubst L1 d e L2 = (thin d e L1 L2).
+
+(* Basic properties *********************************************************)