--- a/doc-src/TutorialI/CTL/PDL.thy Thu Jan 19 21:22:29 2006 +0100
+++ b/doc-src/TutorialI/CTL/PDL.thy Thu Jan 19 21:22:30 2006 +0100
@@ -12,7 +12,7 @@
shown to be equivalent.}
*}
-datatype formula = Atom atom
+datatype formula = Atom "atom"
| Neg formula
| And formula formula
| AX formula