
diff -r 357c395ae838 -r e74c696821a2 handouts/ho04.tex
--- a/handouts/ho04.tex	Tue Aug 23 15:38:20 2016 +0200
+++ b/handouts/ho04.tex	Tue Aug 23 23:12:55 2016 +0200
@@ -25,17 +25,11 @@
 student and I found several rather annoying typos in their
 examples and definitions.} In order to give an answer for
 \emph{how} a regular expression matches a string, Sulzmann and
-Lu introduce \emph{values}. A value will be the output of the
+Lu use \emph{values}. A value will be the output of the
 algorithm whenever the regular expression matches the string.
 If the string does not match the string, an error will be
-raised. Since the first phase of the algorithm by Sulzmann \&
-Lu is identical to the derivative based matcher from the first
-coursework, the function \textit{nullable} will be used to
-decide whether as string is matched by a regular expression.
-If \textit{nullable} says yes, then values are constructed
-that reflect how the regular expression matched the string. 
-
-The definitions for values is given below. They are shown 
+raised. 
+The definition for values is given below. They are shown 
 together with the regular expressions $r$ to which
 they correspond:
 
@@ -60,13 +54,12 @@
       & $\mid$ & $Seq(v_1,v_2)$\\
       & $\mid$ & $\Left(v)$   \\
       & $\mid$ & $Right(v)$  \\
-      & $\mid$ & $[v_1,\ldots\,v_n]$ \\
+      & $\mid$ & $Stars [v_1,\ldots\,v_n]$ \\
 \end{tabular}
 \end{tabular}
 \end{center}
 
-\noindent The reason is that there is a very strong
-correspondence between them. There is no value for the
+\noindent There is no value for the
 $\ZERO$ regular expression, since it does not match any
 string. Otherwise there is exactly one value corresponding to
 each regular expression with the exception of $r_1 + r_2$
@@ -74,7 +67,7 @@
 corresponding to the two alternatives. Note that $r^*$ is
 associated with a list of values, one for each copy of $r$
 that was needed to match the string. This means we might also
-return the empty list $[]$, if no copy was needed in case
+return the empty list $Stars []$, if no copy was needed in case
 of $r^*$. For sequence, there is exactly one value, composed 
 of two component values ($v_1$ and $v_2$).
 




