diff -r 53d18ab990f6 -r 923e4d0d36d5 src/HOL/Library/Multiset.thy
--- a/src/HOL/Library/Multiset.thy	Wed Oct 03 20:54:05 2001 +0200
+++ b/src/HOL/Library/Multiset.thy	Wed Oct 03 20:54:16 2001 +0200
@@ -749,7 +749,7 @@
   apply (blast intro: mult_less_trans)
   done
 
-theorem mult_less_le: "M < N = (M <= N \<and> M \<noteq> (N::'a::order multiset))"
+theorem mult_less_le: "(M < N) = (M <= N \<and> M \<noteq> (N::'a::order multiset))"
   apply (unfold le_multiset_def)
   apply auto
   done