--- a/src/HOL/AxClasses/Group/MonoidGroupInsts.thy	Wed Sep 29 14:40:07 1999 +0200
+++ b/src/HOL/AxClasses/Group/MonoidGroupInsts.thy	Wed Sep 29 14:40:15 1999 +0200
@@ -17,6 +17,6 @@
 (* groups are monoids *)
 
 instance
-  group < monoid                (assoc, left_unit, right_unit)
+  group < monoid                ("Group.assoc", "Group.left_unit", "Group.right_unit")
 
 end