diff -r 4758a6155878 -r 1ab41c59e3d3 hw/hw07.tex --- a/hw/hw07.tex Thu Sep 26 10:39:23 2013 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,75 +0,0 @@ -\documentclass{article} -\usepackage{charter} -\usepackage{hyperref} -\usepackage{amssymb} -\usepackage{amsmath} -\usepackage{tikz} -\usetikzlibrary{automata} - -\newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}% for definitions - -\begin{document} - -\section*{Homework 7} - -\begin{enumerate} -\item Suppose the following finite deterministic automaton over the alphabet $\{0, 1\}$. - -\begin{center} -\begin{tikzpicture}[scale=2, line width=0.5mm] - \node[state, initial, accepting] (q0) at ( 0,1) {$q_0$}; - \node[state, accepting] (q1) at ( 1,1) {$q_1$}; - \node[state] (q2) at ( 2,1) {$q_2$}; - \path[->] (q0) edge[bend left] node[above] {$0$} (q1) - (q1) edge[bend left] node[above] {$1$} (q0) - (q2) edge[bend left=50] node[below] {$1$} (q0) - (q1) edge node[above] {$0$} (q2) - (q2) edge [loop right] node {$0$} () - (q0) edge [loop below] node {$1$} () - ; -\end{tikzpicture} -\end{center} - -Give a regular expression that can recognise the same language as -this automaton. (Hint: If you use Brzozwski's method, you can assume -Arden's lemma which states that an equation of the form $q = q\cdot r + s$ -has the unique solution $q = s \cdot r^*$.) - -\item Consider the following grammar - -\begin{center} -\begin{tabular}{l} -$S \rightarrow N\cdot P$\\ -$P \rightarrow V\cdot N$\\ -$N \rightarrow N\cdot N$\\ -$N \rightarrow A \cdot N$\\ -$N \rightarrow \texttt{student} \;|\; \texttt{trainer} \;|\; \texttt{team} \;|\; \texttt{trains}$\\ -$V \rightarrow \texttt{trains} \;|\; \texttt{team}$\\ -$A \rightarrow \texttt{The} \;|\; \texttt{the}$\\ -\end{tabular} -\end{center} - -where $S$ is the start symbol and $S$, $P$, $N$, $V$ and $A$ are non-terminals. -Using the CYK-algorithm, check whether or not the following string can be parsed -by the grammar: - -\begin{center} -\texttt{The trainer trains the student team} -\end{center} - -\item {\bf (Optional)} The task is to match strings where the letters are in alphabetical order---for example, -\texttt{abcfjz} would pass, but \texttt{acb} would not. Whitespace should be ignored---for example -\texttt{ab c d} should pass. The point is to try to get the regular expression as short as possible! -See: - -\begin{center} -\url{http://callumacrae.github.com/regex-tuesday/challenge11.html} -\end{center} -\end{enumerate} - -\end{document} - -%%% Local Variables: -%%% mode: latex -%%% TeX-master: t -%%% End: