diff -r 01c2744a3786 -r 77349ed89f45 src/HOL/Datatype_Universe.thy
--- a/src/HOL/Datatype_Universe.thy	Thu Oct 12 18:44:35 2000 +0200
+++ b/src/HOL/Datatype_Universe.thy	Fri Oct 13 08:28:21 2000 +0200
@@ -9,7 +9,7 @@
 Could <*> be generalized to a general summation (Sigma)?
 *)
 
-Datatype_Universe = Arithmetic + Sum_Type +
+Datatype_Universe = NatArith + Sum_Type +
 
 
 (** lists, trees will be sets of nodes **)