--- a/handouts/ho04.tex	Sun Oct 15 20:47:14 2017 +0100
+++ b/handouts/ho04.tex	Tue Oct 17 13:49:45 2017 +0100
@@ -5,7 +5,7 @@
 
 
 \begin{document}
-\fnote{\copyright{} Christian Urban, King's College London, 2014, 2015, 2016}
+\fnote{\copyright{} Christian Urban, King's College London, 2014, 2015, 2016, 2017}
 
 \section*{Handout 4 (Sulzmann \& Lu Algorithm)}
 
@@ -28,7 +28,7 @@
 mathematical proof that their algorithm is really correct---the proof 
 Sulzmann \& Lu had originally given contained major flaws. Such correctness
 proofs are important: Kuklewicz maintains a unit-test library
-for the kind of algorithma we are interested in here and he showed 
+for the kind of algorithms we are interested in here and he showed 
 that many implementations in the ``wild'' are buggy, that is not
 satisfy his unit tests:
 
@@ -81,8 +81,8 @@
 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 $Stars []$, if no copy was needed in case
-of $r^*$. For sequence, there is exactly one value, composed 
+return the empty list $Stars []$, if no copy was needed
+for $r^*$. For sequence, there is exactly one value, composed 
 of two component values ($v_1$ and $v_2$).
 
 My implementation of regular expressions and values in Scala is
@@ -381,7 +381,7 @@
 $r_2$ or $r_{2s}$. Unfortunately, this is still not the right
 value in general because there might be some simplifications
 that happened inside $r_2$ and for which the simplification
-function retuned also a rectification function $f_{2s}$. So in
+function returned also a rectification function $f_{2s}$. So in
 fact we need to apply this one too which gives
 
 \begin{center}
@@ -587,7 +587,7 @@
    {\ifodd\value{lstnumber}\color{capri!3}\fi}]{../progs/app61.scala}
 
 \caption{The Scala code for the simplification function. The
-first part defines some auxillary functions for the rectification.
+first part defines some auxiliary functions for the rectification.
 The second part give the simplification function.
 \label{simprect}}
 \end{figure}
@@ -607,7 +607,7 @@
 
 \noindent This corresponds to the $matches$ function we have
 seen in earlier lectures. In the first clause we are given an
-empty string, $[]$, and need to test wether the regular
+empty string, $[]$, and need to test whether the regular
 expression is $nullable$. If yes, we can proceed normally and
 just return the value calculated by $\textit{mkeps}$. The second clause
 is for strings where the first character is $c$, say, and the