Tuned syntax for perm.

--- a/src/HOL/Nominal/Nominal.thy	Thu Dec 22 13:00:53 2005 +0100
+++ b/src/HOL/Nominal/Nominal.thy	Thu Dec 22 13:31:58 2005 +0100
@@ -19,7 +19,7 @@
 
 (* polymorphic operations for permutation and swapping*)
 consts 
-  perm :: "'x prm \<Rightarrow> 'a \<Rightarrow> 'a"     ("_ \<bullet> _" [80,80] 80)
+  perm :: "'x prm \<Rightarrow> 'a \<Rightarrow> 'a"     (infixr "\<bullet>" 80)
   swap :: "('x \<times> 'x) \<Rightarrow> 'x \<Rightarrow> 'x"
 
 (* permutation on sets *)