X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground_2%2Flib%2Fbool.ma;fp=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground_2%2Flib%2Fbool.ma;h=fed25ceda5ee8ce17d1c23c3e6e76e36401b5a8a;hb=928cfe1ebf2fbd31731c8851cdec70802596016d;hp=0000000000000000000000000000000000000000;hpb=cfc43911db215e21036317b26bd1dcf9c3e5d435;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/ground_2/lib/bool.ma b/matita/matita/contribs/lambdadelta/ground_2/lib/bool.ma
new file mode 100644
index 000000000..fed25ceda
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/ground_2/lib/bool.ma
@@ -0,0 +1,30 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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 "basics/bool.ma".
+include "ground_2/notation/constructors/no_0.ma".
+include "ground_2/notation/constructors/yes_0.ma".
+
+(* BOOLEAN PROPERTIES *******************************************************)
+
+interpretation "boolean false" 'no = false.
+
+interpretation "boolean true" 'yes = true.
+
+lemma orb_false_r: ∀b1,b2:bool. (b1 ∨ b2) = false → b1 = false ∧ b2 = false.
+* normalize /2 width=1 by conj/ #b2 #H destruct
+qed-.
+
+lemma commutative_orb: commutative … orb.
+* * // qed.