diff -r 704fd8749dad -r ca4ddf26a7c7 Precedence_ord.thy
--- a/Precedence_ord.thy	Thu Sep 21 14:33:13 2017 +0100
+++ b/Precedence_ord.thy	Fri Sep 22 03:08:30 2017 +0100
@@ -1,9 +1,9 @@
-header {* Order on product types *}
-
 theory Precedence_ord
 imports Main
 begin
 
+section {* Order on product types *}
+
 datatype precedence = Prc nat nat
 
 instantiation precedence :: order