--- a/hws/hw04.tex	Tue Oct 04 15:09:08 2016 +0100
+++ b/hws/hw04.tex	Fri Oct 07 22:08:03 2016 +0100
@@ -10,7 +10,7 @@
 
 \begin{enumerate}
 
-\item If a regular expression $r$ does not contain any occurrence of $\varnothing$,  
+\item If a regular expression $r$ does not contain any occurrence of $\ZERO$,  
 is it possible for $L(r)$ to be empty?
 
 \item Define the tokens and regular expressions for a language
@@ -106,7 +106,9 @@
 %\item (Optional) Modify the tokenizer in \texttt{regexp2.scala} so that it
 %implements the \texttt{findAll} function. This function takes a regular
 %expressions and a string, and returns all substrings in this string that 
-%match the regular expression.
+      %match the regular expression.
+
+\item \POSTSCRIPT  
 \end{enumerate}