--- a/src/FOL/ex/Natural_Numbers.thy Mon Feb 10 14:33:47 2014 +0100
+++ b/src/FOL/ex/Natural_Numbers.thy Mon Feb 10 17:20:11 2014 +0100
@@ -14,7 +14,7 @@
*}
typedecl nat
-arities nat :: "term"
+instance nat :: "term" ..
axiomatization
Zero :: nat ("0") and