--- a/hws/hw06.tex	Fri Apr 10 16:30:52 2020 +0100
+++ b/hws/hw06.tex	Thu Apr 16 19:15:46 2020 +0100
@@ -70,13 +70,21 @@
 recognise the strings (for 1) $ab$ and (for 2) $aaa$. Give in each case
 \emph{all} the values and indicate which one is the POSIX value.
 
+\item Given the regular expression $(a + b)^* \cdot b \cdot (a + b)^*$,
+  which of the following regular expressions are equyivalent
+
+\begin{center}
+\begin{tabular}{ll}    
+  1) & $(ab + bb)^* \cdot (a + b)^*$\\                     % no
+  2) & $(a + b)^* \cdot (ba + bb + b) \cdot (a + b)^*$\\   % yes
+  3) & $(a + b)^* \cdot (a + b) \cdot (a + b)^*$           % no
+\end{tabular}
+\end{center}
+
 \item Parsing combinators consist of atomic parsers, alternative
   parsers, sequence parsers and semantic actions.  What is the purpose
   of (1) atomic parsers and of (2) semantic actions?
 
-
-
-
 \item \POSTSCRIPT        
 \end{enumerate}