--- a/src/HOL/Library/Boolean_Algebra.thy Mon Mar 23 08:14:23 2009 +0100
+++ b/src/HOL/Library/Boolean_Algebra.thy Mon Mar 23 08:14:24 2009 +0100
@@ -5,7 +5,7 @@
header {* Boolean Algebras *}
theory Boolean_Algebra
-imports Plain
+imports Main
begin
locale boolean =