--- a/slides/slides02.tex	Fri Sep 25 17:39:02 2015 +0100
+++ b/slides/slides02.tex	Fri Sep 25 20:59:24 2015 +0100
@@ -117,7 +117,7 @@
 \bl{$\{[], hello, \textit{foobar}, a, abc\}$}
 \end{center}\bigskip
 
-\item \alert{\bf Concatenation} of strings and sets
+\item \alert{\bf Concatenation} of strings and languages
 
 \begin{center}
 \begin{tabular}{rcl}
@@ -152,14 +152,7 @@
   \end{tabular}
   \end{textblock}
   
-  
-\only<2->{\footnotesize
-\begin{textblock}{9}(2,0.5)
-\begin{bubble}[9.8cm]
-\lstinputlisting{../progs/app01.scala}
-\end{bubble}
-\end{textblock}}
-  
+
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
@@ -204,6 +197,19 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
+\frametitle{\begin{tabular}{c}
+ When Are Two Regular\\
+ Expressions Equivalent?\end{tabular}}
+\large
+\begin{center}
+\bl{$r_1 \equiv r_2 \;\;\dn\;\; L(r_1) = L(r_2)$}
+\end{center}  
+  
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[t]
 \frametitle{\begin{tabular}{c}Concrete Equivalences\end{tabular}}