--- a/handouts/ho02.tex	Mon Oct 20 00:28:03 2014 +0100
+++ b/handouts/ho02.tex	Tue Oct 28 06:01:00 2014 +0000
@@ -23,7 +23,7 @@
 \begin{axis}[xlabel={\pcode{a}s},ylabel={time in secs},
     enlargelimits=false,
     xtick={0,5,...,30},
-    xmax=30,
+    xmax=33,
     ymax=35,
     ytick={0,5,...,30},
     scaled ticks=false,
@@ -35,7 +35,7 @@
     legend cell align=left]
 \addplot[blue,mark=*, mark options={fill=white}] 
   table {re-python.data};
-\addplot[brown,mark=pentagon*, mark options={fill=white}] 
+\addplot[brown,mark=triangle*, mark options={fill=white}] 
   table {re-ruby.data};  
 \end{axis}
 \end{tikzpicture}
@@ -44,8 +44,9 @@
   \begin{axis}[xlabel={\pcode{a}s},ylabel={time in secs},
     enlargelimits=false,
     xtick={0,3000,...,12000},
-    xmax=12000,
-    ymax=35,
    ytick={0,5,...,30},
+    xmax=12500,
+    ymax=35,
+    ytick={0,5,...,30},
     scaled ticks=false,
     axis lines=left,
     width=6.5cm,
@@ -291,16 +292,12 @@
 Der\,c\,A\;\dn\;\{s\,|\,c\!::\!s \in A\}
 \]
 
-\noindent
-which essentially transforms a set of strings $A$ by filtering out all
-strings that do not start with $c$ and then strips off the $c$ from
-all the remaining strings. For example suppose $A = \{f\!oo, bar,
-f\!rak\}$ then
-\[
-Der\,f\,A = \{oo, rak\}\quad,\quad
-Der\,b\,A = \{ar\}  \quad \text{and} \quad
-Der\,a\,A = \varnothing
-\]
+\noindent This operation essentially transforms a set of
+strings $A$ by filtering out all strings that do not start
+with $c$ and then strips off the $c$ from all the remaining
+strings. For example suppose $A = \{f\!oo, bar, f\!rak\}$ then
+\[ Der\,f\,A = \{oo, rak\}\quad,\quad Der\,b\,A = \{ar\} \quad
+\text{and} \quad Der\,a\,A = \varnothing \]
  
 \noindent
 Note that in the last case $Der$ is empty, because no string in $A$