\begin{frame}
  \frametitle{Checking Conflict-Serializability}

  \begin{block}{Checking Conflict-Serializability}
    A schedule is \emph{conflict-serializable} if and only if 
    there is \emph{no~cycle} in the precedence graph!
  \end{block}
  \pause
  
   \begin{exampleblock}{}
    {\def\scheduleWidth{1cm}
    \begin{tcenter}
      \begin{tikzpicture}[node distance=15mm]
        \schedule{}{2}{1wV|2rV|1wV}

        \node (t1) at (6.5cm,-\scheduleHeight) {$T_1$}; 
        \node (t2) [right of=t1] {$T_2$}; 
        \draw [very thick,->] (t1) to[bend left=30] (t2);
        \draw [very thick,->] (t2) to[bend left=30] (t1);

        \begin{scope}[yshift=-1.45cm]
        \schedule{}{2}{1rV|2rV|1wV}

        \node (t1) at (6.5cm,-\scheduleHeight) {$T_1$}; 
        \node (t2) [right of=t1] {$T_2$}; 
        \draw [very thick,<-] (t1) -- (t2);

        \end{scope}
        \begin{scope}[yshift=-2.9cm]
        \schedule{}{3}{2rV|3wV|1wY|2rY|2wZ}

        \node (t1) at (6.5cm,-\scheduleHeight) {$T_1$}; 
        \node (t3) [below right of=t1] {$T_3$}; 
        \node (t2) [above right of=t3] {$T_2$}; 
        \draw [very thick,->] (t1) -- (t2);
        \draw [very thick,->] (t2) -- (t3);
        \end{scope}
      \end{tikzpicture}
    \end{tcenter}
    }
    \pause
    Schedules $2$ and $3$ have no cycles in their precedence graph.
    They are conflict serializable!
  \end{exampleblock}
\end{frame}