--- a/handouts/ho04.tex	Sun Nov 02 09:10:15 2014 +0000
+++ b/handouts/ho04.tex	Mon Nov 03 16:17:58 2014 +0000
@@ -95,7 +95,7 @@
 regular expression, say $r_1$, matches the string $abc$. We
 first build the three derivatives (according to $a$, $b$ and
 $c$). We then use $nullable$ to find out whether the resulting
-regular expression can match the empty string. If yes we call
+regular expression can match the empty string. If yes, we call
 the function $mkeps$.
 
 \begin{figure}[t]
@@ -140,7 +140,7 @@
 \end{tabular}
 \end{center}
 
-\noindent There are no cases for $\epsilon$ and $c$, since
+\noindent There are no cases for $\varnothing$ and $c$, since
 these regular expression cannot match the empty string. Note
 also that in case of alternatives we give preference to the
 regular expression on the left-hand side. This will become
@@ -172,7 +172,7 @@
 
 \noindent This definition is by recursion on the regular
 expression and by analysing the shape of the values. Therefore
-there are, for example, three cases for sequnece regular
+there are, for example, three cases for sequence regular
 expressions. The last clause for the star regular expression
 returns a list where the first element is $inj\,r\,c\,v$ and
 the other elements are $vs$. That means $\_\,::\,\_$ should be