--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ex/pl0.thy	Tue Mar 22 08:28:31 1994 +0100
@@ -0,0 +1,16 @@
+(*  Title: 	HOL/ex/pl0.thy
+    ID:         $Id$
+    Author: 	Tobias Nipkow
+    Copyright   1994  TU Muenchen
+
+Syntax of propositional logic formulae.
+*)
+
+PL0 = HOL +
+types 'a pl
+arities pl :: (term)term
+consts
+    false	:: "'a pl"
+    "->"	:: "['a pl,'a pl] => 'a pl"	(infixr 90)
+    var		:: "'a => 'a pl"		("#_")
+end