diff -r 67b3933c3190 -r 7b1470b55936 Nominal/Nominal2_FSet.thy
--- a/Nominal/Nominal2_FSet.thy	Sat Sep 04 06:10:04 2010 +0800
+++ b/Nominal/Nominal2_FSet.thy	Sat Sep 04 06:23:31 2010 +0800
@@ -9,11 +9,8 @@
   shows "(op = ===> list_eq ===> list_eq) permute permute"
   apply(simp)
   apply(clarify)
-  apply(simp add: eqvts[symmetric])  
-  apply(subst permute_minus_cancel(1)[symmetric, of "xb"])
-  apply(subst mem_eqvt[symmetric])
-  apply(subst (2) permute_minus_cancel(1)[symmetric, of "xb"])
-  apply(subst mem_eqvt[symmetric])
+  apply(rule_tac p="-x" in permute_boolE)
+  apply(perm_simp add: permute_minus_cancel)
   apply(simp)
   done