Delete useless slide.

doc/nextml2015/presentation.tex

@@ -1137,13 +1137,6 @@ The result is then sliced to obtain the pre-nonlinearity activations for i, f, $
 \end{itemize}
 \end{frame}
 
-\begin{frame}
-  \frametitle{}
-\begin{itemize}
-\item a
-\end{itemize}
-\end{frame}
-
 \section{Exercices}
 \begin{frame}{Exercices}
 \begin{itemize}