\begin{frame} \small \vspace{-1ex} \begin{block}{Summary} \begin{center} \begin{tikzpicture}[on grid,node distance=16mm and 29mm] \node (1) {\alert<1-6>{CR}}; \node (2) [above left=of 1] {\alert<1,5,6>{SN}}; \node (3) [above right=of 1] {\alert<1-4,6>{WN}}; \node (4) [below left=of 1] {\alert<1,3-4,6>{WCR}}; \node (5) [below right=of 1,xshift=-11mm] {\alert<1,3-4,6>{NF}}; \begin{scope}[node distance=11mm] \node (5') [right=of 5] {\alert<1,3-4,6>{\UN}}; \node (5'') [right=of 5'] {\alert<1,3-4,6>{\UNrew}}; \end{scope} \node (6) [node distance=2cm,left=of 1] {\&}; \node (7) [node distance=2cm,right=of 1] {\&}; \draw[->] (1) edge[bend left] (4); \draw[->] (1) edge[bend right] (5); \draw[->] (2) edge (3); \draw[->] (2) edge[bend right] (1); \draw[->] (3) edge[bend left] (1); \draw[->] (4) edge[bend left] (1); \draw[->] (5'') edge[bend right=20] (1); \draw[->] (5) edge (5'); \draw[->] (5') edge (5''); \end{tikzpicture} \end{center} \end{block} \begin{definitions}<2-> \begin{itemize} \item \makebox[3cm][l]{\alert<2-4>{semi-completeness}} \begin{itemize} \item CR \& WN \item<4-> every element has unique normal form \end{itemize} \item<5-> \makebox[3cm][l]{\alert<5,6>{completeness}} \begin{itemize} \item CR \& SN \smallskip \end{itemize} \end{itemize} \end{definitions} \end{frame}