diff -r 9537bf1c4853 -r 5b7a9633cfa8 src/FOL/ex/Propositional_Cla.thy
--- a/src/FOL/ex/Propositional_Cla.thy	Sun Nov 02 18:21:14 2014 +0100
+++ b/src/FOL/ex/Propositional_Cla.thy	Sun Nov 02 18:21:45 2014 +0100
@@ -3,7 +3,7 @@
     Copyright   1991  University of Cambridge
 *)
 
-header {* First-Order Logic: propositional examples (classical version) *}
+section {* First-Order Logic: propositional examples (classical version) *}
 
 theory Propositional_Cla
 imports FOL