\begin{frame} \begin{block}{Newman's Lemma} \smallskip SN \& WCR \quad$\Rightarrow$\quad CR\strut \end{block} \bigskip \begin{definition}<2->[WCR] \hspace{-1.5ex} \begin{tikzpicture}[on grid,baseline=(1).baseline] \node (1) {$\strut \alert<3>{a}$}; \node (2) [below left=of 1] {$\alert<3>{b}$}; \node (3) [below right=of 1] {$\alert<3>{c}$}; \node (4) [below right=of 2] {$\strut d$}; \node (5) [left=of 1] {\makebox[3cm][l]{$\strut \forall a,b,c$}}; \node (6) [left=of 4] {\makebox[3cm][l]{$\strut \exists d$}}; \alert<3>{\draw[->] (1) -- (2);} \alt<3->{ \alert<3>{\draw[->] (1) -- (3) node[midway] {\hspace{35mm}peak};} }{ \draw[->] (1) -- (3); } \draw[dotted,->>] (2) -- (4); \draw[dotted,->>] (3) -- (4); \end{tikzpicture} \end{definition} \bigskip \begin{block}<4->{Question} \smallskip How to prove WCR ?\strut \end{block} \end{frame}