diff -r 55c85d25e18c -r 4f5ab843cf5b src/HOL/Auth/Auth_Shared.thy
--- a/src/HOL/Auth/Auth_Shared.thy	Thu Dec 10 21:31:24 2015 +0100
+++ b/src/HOL/Auth/Auth_Shared.thy	Thu Dec 10 21:39:33 2015 +0100
@@ -2,7 +2,7 @@
     Copyright   1996  University of Cambridge
 *)
 
-section {* Conventional protocols: rely on conventional Message, Event and Public -- Shared-key protocols *}
+section \<open>Conventional protocols: rely on conventional Message, Event and Public -- Shared-key protocols\<close>
 
 theory Auth_Shared
 imports