fixed update syntax;

--- a/src/HOLCF/IMP/Denotational.thy	Thu May 07 18:34:48 1998 +0200
+++ b/src/HOLCF/IMP/Denotational.thy	Fri May 08 10:15:39 1998 +0200
@@ -16,7 +16,7 @@
 
 primrec D com
   "D(SKIP) = (LAM s. Def(undiscr s))"
-  "D(X := a) = (LAM s. Def((undiscr s)[a(undiscr s)/X]))"
+  "D(X := a) = (LAM s. Def((undiscr s)[X := a(undiscr s)]))"
   "D(c0 ; c1) = (dlift(D c1) oo (D c0))"
   "D(IF b THEN c1 ELSE c2) =
 	(LAM s. if b(undiscr s) then (D c1)`s else (D c2)`s)"