--- a/src/HOL/Lex/Prefix.thy Tue Jun 27 20:35:31 2000 +0200
+++ b/src/HOL/Lex/Prefix.thy Tue Jun 27 23:43:46 2000 +0200
@@ -6,7 +6,7 @@
Prefix = Main +
-arities list :: (term)ord
+instance list :: (term)ord
defs
prefix_def "xs <= zs == ? ys. zs = xs@ys"