diff -r 1d80798e8d8a -r b27bbb021df1 src/HOL/Library/Mapping.thy
--- a/src/HOL/Library/Mapping.thy	Fri Oct 12 15:08:29 2012 +0200
+++ b/src/HOL/Library/Mapping.thy	Fri Oct 12 18:58:20 2012 +0200
@@ -8,7 +8,7 @@
 
 subsection {* Type definition and primitive operations *}
 
-typedef (open) ('a, 'b) mapping = "UNIV :: ('a \<rightharpoonup> 'b) set"
+typedef ('a, 'b) mapping = "UNIV :: ('a \<rightharpoonup> 'b) set"
   morphisms lookup Mapping ..
 
 lemma lookup_Mapping [simp]: