diff -r 78a9bca983ac -r a48818595670 src/Pure/sorts.ML
--- a/src/Pure/sorts.ML	Fri Jul 07 18:29:34 2000 +0200
+++ b/src/Pure/sorts.ML	Fri Jul 07 21:51:52 2000 +0200
@@ -130,7 +130,7 @@
   in intr S end;
 
 (*instersect sorts (preserves minimality)*)
-fun inter_sort classrel = foldr (inter_class classrel);
+fun inter_sort classrel = sort_strings o foldr (inter_class classrel);