diff -r 9a431d1eac85 -r b7f9460c6a1c coursework/cw01.tex
--- a/coursework/cw01.tex	Fri Apr 10 12:11:19 2020 +0100
+++ b/coursework/cw01.tex	Fri Apr 10 16:12:33 2020 +0100
@@ -125,7 +125,7 @@
 From the
 lectures you have seen the definitions for the functions
 \textit{nullable} and \textit{der} for the basic regular
-expressions. Implement and write down rules for the extended
+expressions. Implement and write down the rules for the extended
 regular expressions:
 
 \begin{center}
@@ -170,20 +170,21 @@
 
 \begin{center}
 \def\arraystretch{1.2}  
-\begin{tabular}{r|m{12mm}|m{12mm}|m{12mm}|m{12mm}|m{12mm}|m{12mm}}
-  string & $a^{\{3\}}$ & $(a^?)^{\{3\}}$ & $a^{\{..3\}}$ &
-     $(a^?)^{\{..3\}}$ & $a^{\{3..5\}}$ & $(a^?)^{\{3..5\}}$\\\hline
-  $[]$           &&&&&& \\\hline 
-  \texttt{a}     &&&&&& \\\hline 
-  \texttt{aa}    &&&&&& \\\hline 
-  \texttt{aaa}   &&&&&& \\\hline 
-  \texttt{aaaaa} &&&&&& \\\hline 
-  \texttt{aaaaaa}&&&&&& \\
+\begin{tabular}{@{}r|m{6mm}|m{6mm}|m{6mm}|m{10mm}|m{10mm}|m{10mm}|m{10mm}|m{10mm}}
+  string & $a^?$ & $\sim{}a$ & $a^{\{3\}}$ & $(a^?)^{\{3\}}$ & $a^{\{..3\}}$ &
+     $(a^?)^{\{..3\}}$ & $a^{\{3..5\}}$ & $(a^?)^{\{3..5\}}$ \\\hline
+  $[]$           &&&&&&& \\\hline 
+  \texttt{a}     &&&&&&& \\\hline 
+  \texttt{aa}    &&&&&&& \\\hline 
+  \texttt{aaa}   &&&&&&& \\\hline 
+  \texttt{aaaaa} &&&&&&& \\\hline 
+  \texttt{aaaaaa}&&&&&&& \\
 \end{tabular}
 \end{center}
 
 \noindent
-Does your matcher produce the expected results?
+Does your matcher produce the expected results? Make sure you
+also test corner-cases, like $a^{\{0\}}$!
 
 \subsection*{Question 4}