\begin{frame}{Deterministic Pushdown Automata} \begin{block}{} A \emph{deterministic pushdown automaton} (\emph{DPDA}) is an NPDA such that \begin{itemize} \item $\delta(q,\alert{\alpha},b)$ contains at most one element \item If $\delta(q,\alert{\lambda},b) \neq \emptyset$, then $\delta(q,\alert{a},b) = \emptyset$ for every $a \in \Sigma$. \end{itemize} \end{block} \pause\medskip \begin{block}{} A language $L$ is \emph{deterministic context-free} if there exists a DPDA $M$ with $L(M) = L$. \end{block} \medskip A deterministic context-free $L$ allows for \alert{efficient parsing}. \end{frame}