--- a/handouts/ho03.tex	Sat Oct 13 13:51:28 2018 +0100
+++ b/handouts/ho03.tex	Tue Oct 16 00:42:10 2018 +0100
@@ -1355,15 +1355,15 @@
 \end{eqnarray}
  
 \noindent Unfortunately we cannot make any more progress with
-substituting equations, because both (6) and (7) contain the
+substituting equations, because both (8) and (9) contain the
 variable on the left-hand side also on the right-hand side.
 Here we need to now use a law that is different from the usual
 laws about linear equations. It is called \emph{Arden's rule}.
 It states that if an equation is of the form $q = q\,r + s$
 then it can be transformed to $q = s\, r^*$. Since we can
-assume $+$ is symmetric, Equation (7) is of that form: $s$ is
+assume $+$ is symmetric, Equation (9) is of that form: $s$ is
 $Q_0\,a\,a$ and $r$ is $a$. That means we can transform
-(7) to obtain the two new equations
+(9) to obtain the two new equations
 
 \begin{eqnarray}
 Q_0 & = & \ONE + Q_0\,(b + a\,b) +  Q_2\,b\\