- we are committing just the components before "reducibility"

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / substitution / ldrops_ldrops.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/substitution/ldrops_ldrops.ma b/matita/matita/contribs/lambdadelta/basic_2/substitution/ldrops_ldrops.ma
new file mode 100644 (file)
index 0000000..a4dbfb0
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/basic_2/substitution/ldrops_ldrops.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/substitution/ldrops_ldrop.ma".
+
+(* GENERIC LOCAL ENVIRONMENT SLICING ****************************************)
+
+(* Main properties **********************************************************)
+
+(* Basic_1: was: drop1_trans *)
+theorem ldrops_trans: ∀L,L2,des2. ⇩*[des2] L ≡ L2 → ∀L1,des1. ⇩*[des1] L1 ≡ L →
+                      ⇩*[des2 @@ des1] L1 ≡ L2.
+#L #L2 #des2 #H elim H -L -L2 -des2 // /3 width=3/
+qed.