\begin{frame}
\small

\begin{definition}[Operations on Terms]
\smallskip
\begin{itemize}
\item
$\alert<1>{\rt(\:\cdot\:)}$, the \alert<1>{root of a term} \\[1ex]
\(
\rt(t) = \begin{cases}
t & \text{if $t \in \VV$} \\[.5ex]
f & \text{if $t = f(\seq{t})$}
\end{cases}
\)
\end{itemize}
\end{definition}

\vfill

\begin{example}<2->
\smallskip
\GREEN{$(2:x)\alert<2>{+}((1:x):y)$} \qquad
\GREEN{\begin{tikzpicture}[on grid,baseline=(1).baseline]
\matrix[ampersand replacement=\&,row sep=5mm]{
\& \& \& \node (1) {\alert<2>{$+$}}; \& \& \& \\
\& \node (2) {$:$}; \& \& \& \& \node (3) {$:$}; \& \\
\node (4) {$2$}; \& \& \node (5) {$x$}; \& \& \node (6) {$:$}; \& \&
\node (7) {$y$}; \\
\& \& \& \node (8) {$1$}; \& \& \node (9) {$x$}; \& \\};
\draw (1) -- (2) (1) -- (3);
\draw (2) -- (4) (2) -- (5);
\draw (3) -- (6) (3) -- (7);
\draw (6) -- (8) (6) -- (9);
\end{tikzpicture}}
\end{example}

\end{frame}