diff -r 6146e275e8af -r 33ba3faeaa0e src/HOL/Word/WordArith.thy
--- a/src/HOL/Word/WordArith.thy	Wed Jan 28 06:03:46 2009 -0800
+++ b/src/HOL/Word/WordArith.thy	Wed Jan 28 16:57:12 2009 +0100
@@ -1001,7 +1001,7 @@
   apply (auto simp add: unat_def uint_sub_if')
    apply (rule nat_diff_distrib)
     prefer 3
-    apply (simp add: group_simps)
+    apply (simp add: algebra_simps)
     apply (rule nat_diff_distrib [THEN trans])
       prefer 3
       apply (subst nat_add_distrib)