diff -r e3bbc2c4c581 -r 20d01210b9b1 src/HOL/Map.thy
--- a/src/HOL/Map.thy	Mon Apr 20 12:27:23 2009 +0200
+++ b/src/HOL/Map.thy	Mon Apr 20 16:28:13 2009 +0200
@@ -11,7 +11,7 @@
 imports List
 begin
 
-types ('a,'b) "~=>" = "'a => 'b option"  (infixr 0)
+types ('a,'b) "~=>" = "'a => 'b option"  (infixr "~=>" 0)
 translations (type) "a ~=> b " <= (type) "a => b option"
 
 syntax (xsymbols)