diff -r 4758a6155878 -r 1ab41c59e3d3 hw/hw03.tex
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+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
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-\documentclass{article}
-\usepackage{charter}
-\usepackage{hyperref}
-\usepackage{amssymb}
-\usepackage{amsmath}
-
-\begin{document}
-
-\section*{Homework 3}
-
-\begin{enumerate}
-\item Assume you have an alphabet consisting of the letters $a$, $b$ and $c$ only.
-(a) Find a regular expression that recognises the two strings $ab$ and $ac$. (b)
-Find a regular expression that matches all strings \emph{except} these two strings.
-Note, you can only use regular expressions of the form 
-\begin{center}
-$r ::= \varnothing \;|\; \epsilon \;|\; c  \;|\; r_1 + r_2  \;|\; r_1 \cdot r_2 \;|\; r^*$
-\end{center}
-
-\item Define the function $zeroable$ which takes a regular expression as argument
-and returns a boolean.\footnote{In an earlier version there was an error.} The 
-function should satisfy the following property:
-\begin{center}
-$zeroable(r)$ \;if and only if\; $L(r) = \varnothing$
-\end{center}
-
-\item Define the tokens and regular expressions for a language
-consisting of numbers, left-parenthesis (, right-parenthesis ),
-identifiers and the operations $+$, $-$ and $*$. Can the following strings 
-in this language be lexed?
-
-\begin{itemize}
-\item \texttt{"}$(a + 3) * b$\texttt{"}
-\item \texttt{"}$)()++ -33$\texttt{"}
-\item \texttt{"}$(a / 3) * 3$\texttt{"}
-\end{itemize}
-
-
-In case they can, can you give the corresponding token sequences.
-\end{enumerate}
-
-
-
-\end{document}
-
-%%% Local Variables: 
-%%% mode: latex
-%%% TeX-master: t
-%%% End: