--- a/hws/hw04.tex	Mon Oct 05 04:05:20 2015 +0100
+++ b/hws/hw04.tex	Thu Oct 08 14:06:18 2015 +0100
@@ -6,6 +6,8 @@
 
 \section*{Homework 4}
 
+\HEADER
+
 \begin{enumerate}
 
 \item If a regular expression $r$ does not contain any occurrence of $\varnothing$,