X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Fbasics%2Fsets.ma;fp=matita%2Fmatita%2Flib%2Fbasics%2Fsets.ma;h=cdc6ac9e8e278e19c3d7957bf600f7150ae1d895;hb=d2b59bd89f761a16a2dbc663f446b4f95c767b83;hp=43b22bff6900c1a329610a05596c4a37b41346a6;hpb=7f06a5a1b90a9fb9f1742cb8a469821148e0b9f9;p=helm.git

diff --git a/matita/matita/lib/basics/sets.ma b/matita/matita/lib/basics/sets.ma
index 43b22bff6..cdc6ac9e8 100644
--- a/matita/matita/lib/basics/sets.ma
+++ b/matita/matita/lib/basics/sets.ma
@@ -13,7 +13,7 @@ include "basics/logic.ma".
 
 (**** a subset of A is just an object of type A→Prop ****)
 
-definition empty_set ≝ λA:Type[0].λa:A.⊥.
+definition empty_set ≝ λA:Type[0].λa:A.False.
 notation "\emptyv" non associative with precedence 90 for @{'empty_set}.
 interpretation "empty set" 'empty_set = (empty_set ?).