diff -r 9537bf1c4853 -r 5b7a9633cfa8 src/HOL/UNITY/Union.thy
--- a/src/HOL/UNITY/Union.thy	Sun Nov 02 18:21:14 2014 +0100
+++ b/src/HOL/UNITY/Union.thy	Sun Nov 02 18:21:45 2014 +0100
@@ -5,7 +5,7 @@
 Partly from Misra's Chapter 5: Asynchronous Compositions of Programs.
 *)
 
-header{*Unions of Programs*}
+section{*Unions of Programs*}
 
 theory Union imports SubstAx FP begin