Binary file hws/hw01.pdf has changed

--- a/hws/hw01.tex	Mon Sep 15 04:42:48 2014 +0100
+++ b/hws/hw01.tex	Mon Sep 15 04:54:01 2014 +0100
@@ -1,46 +1,62 @@
 \documentclass{article}
-\usepackage{charter}
-\usepackage{hyperref}
-\usepackage{amssymb}
+\usepackage{../style}
 
 \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
+
+\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)? 
+      If you want to follow the code I present during the
+      lectures, read the handout about Scala.
+
+\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? (For example in cases there
+      are links that appear on different recursion levels, the
+      crawlers visit such web-pages several times. Can this be
+      avoided?) 
 
-\item Read the handout of the first lecture and make sure you
-understand the concepts of strings and languages. 
+\item Read the handout of the first lecture and the handout
+      about notation. Make sure you understand the concepts of
+      strings and languages. 
 
-\item In the context of the AFL-course, what is meant by the term \emph{language}?
+\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 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 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 strings
-are in $A @ B$?
+\item Assume a set $A$ contains 4 strings and a set $B$ 7
+      strings, how many strings are in $A @ B$?
+
+\item How is the power of a language defined? (Hint: There are
+      two rules, one for $\_^0$ and one for
+      $\_^{n+1}$.)
 
-\item How is the power of a language defined? (Hint: There are two rules, one for $\_\!\_^0$ and
-one for $\_\!\_^{n+1}$.)
+\item How many regular expressions are there to match the
+      string $abc$? (How many if they cannot include
+      $\epsilon$ and $\varnothing$? How many if they also are
+      not allowed to contain stars? How many if they also are
+      not allowed to contain $\_ + \_$?)
 
-\item How many regular expressions are there to match the string $abc$? 
-(How many if they cannot include $\epsilon$ and $\varempty$? 
-How many if they also are not allowed to contain stars?
-How many if they also are not allowed to contain $+$?)
+\item When are two regular expressions equivalent? Can you
+      think of instances where two regular expressions are
+      equivalent, but it is not so obvious that they are? For
+      example $a + b$ and $b + a$ do not count\ldots they
+      are obviously equivalent.
 
 \end{enumerate}