diff -r 16d56796f5a0 -r d679c1f837a7 src/Tools/isac/calcelems.sml
--- a/src/Tools/isac/calcelems.sml	Mon Sep 13 17:21:22 2010 +0200
+++ b/src/Tools/isac/calcelems.sml	Mon Sep 13 18:12:15 2010 +0200
@@ -346,8 +346,9 @@
 (*rewrite orders, also stored in 'type met' and type 'and rls'
   The association list is required for 'rewrite.."rew_ord"..'
   WN0509 tests not well-organized: see smltest/Knowledge/termorder.sml*)
-val rew_ord' = 
-    ref ([]:(rew_ord' *        (*the key for the association list         *)
+val rew_ord' =
+    Unsynchronized.ref
+        ([]:(rew_ord' *        (*the key for the association list         *)
 	     (subst 	       (*the bound variables - they get high order*)
 	      -> (term * term) (*(t1, t2) to be compared                  *)
 	      -> bool))        (*if t1 <= t2 then true else false         *)