--- a/Nominal-General/nominal_library.ML	Mon Jul 26 09:19:28 2010 +0200
+++ b/Nominal-General/nominal_library.ML	Tue Jul 27 09:09:02 2010 +0200
@@ -112,7 +112,7 @@
   | mk_union (@{term "{}::atom set"}, t2) = t2
   | mk_union (t1, t2) = HOLogic.mk_binop @{const_name "sup"} (t1, t2)  
  
-fun fold_union trms = fold (curry mk_union) trms @{term "{}::atom set"}
+fun fold_union trms = fold_rev (curry mk_union) trms @{term "{}::atom set"}