--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hws/hw02.tex	Thu Sep 26 10:41:47 2013 +0100
@@ -0,0 +1,36 @@
+\documentclass{article}
+\usepackage{charter}
+\usepackage{hyperref}
+\usepackage{amssymb}
+\usepackage{amsmath}
+
+\begin{document}
+
+\section*{Homework 2}
+
+\begin{enumerate}
+\item Give regular expressions for (a) decimal numbers and for (b) binary numbers. 
+(Hint: Observe that the empty string is not a number. Also observe that leading 0s 
+are normally not written.)
+
+\item Decide whether the following two regular expressions are equivalent $(\epsilon + a)^* \equiv^? a^*$ and 
+$(a \cdot b)^* \cdot a \equiv^? a \cdot (b \cdot a)^*$.
+
+\item Given the regular expression $r = (a \cdot b + b)^*$. Compute what the derivative of $r$ is with respect to
+$a$ and $b$. Is $r$ nullable?
+
+\item What is a regular language?
+
+\item Prove that for all regular expressions $r$ we have
+\begin{center}
+$\text{nullable}(r)$ \quad if and only if \quad $\texttt{""} \in L(r)$
+\end{center}
+
+\end{enumerate}
+
+\end{document}
+
+%%% Local Variables: 
+%%% mode: latex
+%%% TeX-master: t
+%%% End: