src/HOL/Tools/BNF/bnf_util.ML
changeset 62343 24106dc44def
parent 62324 ae44f16dcea5
child 63222 fe92356ade42
--- a/src/HOL/Tools/BNF/bnf_util.ML	Wed Feb 17 21:51:55 2016 +0100
+++ b/src/HOL/Tools/BNF/bnf_util.ML	Wed Feb 17 21:51:56 2016 +0100
@@ -257,8 +257,12 @@
   Const (@{const_name Bex}, fastype_of X --> fastype_of f --> HOLogic.boolT) $ X $ f;
 
 fun mk_UNION X f =
-  let val (T, U) = dest_funT (fastype_of f);
-  in Const (@{const_name SUPREMUM}, fastype_of X --> (T --> U) --> U) $ X $ f end;
+  let
+    val (T, U) = dest_funT (fastype_of f);
+  in
+    Const (@{const_name Sup}, HOLogic.mk_setT U --> U)
+      $ (Const (@{const_name image}, (T --> U) --> fastype_of X --> HOLogic.mk_setT U) $ f $ X)
+  end;
 
 fun mk_Union T =
   Const (@{const_name Sup}, HOLogic.mk_setT (HOLogic.mk_setT T) --> HOLogic.mk_setT T);