diff -r e2c0d8ef29cb -r c399ae4b836f src/ZF/Induct/Ntree.thy
--- a/src/ZF/Induct/Ntree.thy	Sun Nov 02 16:09:35 2014 +0100
+++ b/src/ZF/Induct/Ntree.thy	Sun Nov 02 16:39:54 2014 +0100
@@ -3,7 +3,7 @@
     Copyright   1994  University of Cambridge
 *)
 
-header {* Datatype definition n-ary branching trees *}
+section {* Datatype definition n-ary branching trees *}
 
 theory Ntree imports Main begin