--- a/src/Doc/Tutorial/CTL/PDL.thy Fri Sep 27 22:44:30 2024 +0200
+++ b/src/Doc/Tutorial/CTL/PDL.thy Fri Sep 27 23:47:45 2024 +0200
@@ -26,7 +26,7 @@
\hbox{\<open>valid s f\<close>}. The definition is by recursion over the syntax:
\<close>
-primrec valid :: "state \<Rightarrow> formula \<Rightarrow> bool" (\<open>(_ \<Turnstile> _)\<close> [80,80] 80)
+primrec valid :: "state \<Rightarrow> formula \<Rightarrow> bool" ("(_ \<Turnstile> _)" [80,80] 80)
where
"s \<Turnstile> Atom a = (a \<in> L s)" |
"s \<Turnstile> Neg f = (\<not>(s \<Turnstile> f))" |