diff -r e2c0d8ef29cb -r c399ae4b836f src/ZF/Cardinal_AC.thy
--- a/src/ZF/Cardinal_AC.thy	Sun Nov 02 16:09:35 2014 +0100
+++ b/src/ZF/Cardinal_AC.thy	Sun Nov 02 16:39:54 2014 +0100
@@ -5,7 +5,7 @@
 These results help justify infinite-branching datatypes
 *)
 
-header{*Cardinal Arithmetic Using AC*}
+section{*Cardinal Arithmetic Using AC*}
 
 theory Cardinal_AC imports CardinalArith Zorn begin