--- a/Subst/subst.thy	Thu Feb 24 14:45:57 1994 +0100
+++ b/Subst/subst.thy	Wed Mar 02 12:26:55 1994 +0100
@@ -26,7 +26,7 @@
 \                          %x.Const(x),			\
 \                          %u v q r.Comb(q,r))"
 
-  comp_def     "al <> bl == alist_rec(al,bl,%x y xs g.Cons(<x,y <| bl>,g))"
+  comp_def     "al <> bl == alist_rec(al,bl,%x y xs g.<x,y <| bl>#g)"
 
   sdom_def
   "sdom(al) == alist_rec(al, {},  \