diff -r 6793b02a3409 -r ddf1f03a9ad9 src/HOL/Tools/metis_tools.ML
--- a/src/HOL/Tools/metis_tools.ML	Wed Oct 21 12:02:19 2009 +0200
+++ b/src/HOL/Tools/metis_tools.ML	Wed Oct 21 12:02:56 2009 +0200
@@ -631,7 +631,7 @@
         let val (mth, tfree_lits) = hol_thm_to_fol is_conjecture ctxt mode ith
         in
            {axioms = (mth, Meson.make_meta_clause ith) :: axioms,
-            tfrees = union (op =) (tfree_lits, tfrees)}
+            tfrees = union (op =) tfree_lits tfrees}
         end;
       val lmap0 = List.foldl (add_thm true)
                         {axioms = [], tfrees = init_tfrees ctxt} cls