--- a/src/HOL/IOA/meta_theory/IOA.thy Mon Sep 23 18:26:51 1996 +0200
+++ b/src/HOL/IOA/meta_theory/IOA.thy Tue Sep 24 08:59:24 1996 +0200
@@ -6,7 +6,7 @@
The I/O automata of Lynch and Tuttle.
*)
-IOA = Asig +
+IOA = Asig + Option +
types
'a seq = "nat => 'a"