\documentclass{article}\usepackage{charter}\usepackage{hyperref}\usepackage{amssymb}\begin{document}\section*{Homework 1}\begin{enumerate}\item {\bf (Optional)} If you want to run the code presented in the lectures, install the Scala programming language available (for free) from\begin{center}\url{http://www.scala-lang.org}\end{center}\item {\bf (Optional)} Have a look at the crawler programs. Can you find a usage for them in your daily programming life?Can you improve them (in cases they are linked on different levels, they visit web-pages several times)? \item Read the handout of the first lecture and make sure youunderstand the concepts of strings and languages. \item In the context of the AFL-course, what is meant by the term \emph{language}?\item Give the definition for regular expressions. What is the meaning of a regular expression?\item Assume the concatenation operation of two strings is written as $s_1 @ s_2$. Define the operation of \emph{concatenating} two sets of strings.\item Assume a set $A$ contains 4 strings and a set $B$ 7 strings, how many stringsare in $A @ B$?\item How is the power of a language defined? (Hint: There are two rules, one for $\_\!\_^0$ andone for $\_\!\_^{n+1}$.)\end{enumerate}\end{document}%%% Local Variables: %%% mode: latex%%% TeX-master: t%%% End: