diff -r 3aea60ca3900 -r 06a48bbeb22a src/Pure/library.ML
--- a/src/Pure/library.ML	Thu Oct 22 16:52:06 2009 +0200
+++ b/src/Pure/library.ML	Thu Oct 22 16:58:22 2009 +0200
@@ -174,6 +174,7 @@
   (*lists as multisets*)
   val remove1: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
   val combine: ('a * 'a -> bool) -> 'a list -> 'a list -> 'a list
+  val submultiset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
 
   (*orders*)
   val is_equal: order -> bool
@@ -863,6 +864,9 @@
 
 fun combine eq xs ys = fold (remove1 eq) ys xs @ ys;
 
+fun submultiset _ ([], _)  = true
+  | submultiset eq (x :: xs, ys) = member eq ys x andalso submultiset eq (xs, remove1 eq x ys);
+
 
 
 (** orders **)