--- a/hws/hw01.tex Mon Oct 06 20:55:16 2014 +0100
+++ b/hws/hw01.tex Fri Oct 10 16:59:22 2014 +0100
@@ -7,58 +7,51 @@
\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}
- 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?)
+ If you want to follow the code I present during the lectures,
+ read the handout about Scala.
-\item Read the handout of the first lecture and the handout
- about notation. Make sure you understand the concepts of
- strings and languages.
+\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 In the context of the AFL-course, what is meant by the
- term \emph{language}?
+\item Read the handout of the first lecture and the handout about
+ notation. Make sure you understand the concepts of strings and
+ languages. 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? (Hint: The meaning is defined recursively.)
-\item Assume the concatenation operation of two strings is
- written as $s_1 @ s_2$. Define the operation of
- \emph{concatenating}, written $\_ \,@\, \_$ 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}, written
+ $\_ \,@\, \_$ 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 are also
- not allowed to contain stars? How many if they are also
- not allowed to contain $\_ + \_$?
+\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 are also not allowed to contain stars? How many if
+ they are also not allowed to contain $\_ + \_$?
-\item When are two regular expressions equivalent? Can you
- think of instances where two regular expressions match
- the same strings, but it is not so obvious that they do? For
- example $a + b$ and $b + a$ do not count\ldots they
- obviously match the same strings, namely $[a]$ and $[b]$.
-
+\item When are two regular expressions equivalent? Can you think of
+ instances where two regular expressions match the same strings, but
+ it is not so obvious that they do? For example $a + b$ and $b + a$
+ do not count\ldots they obviously match the same strings, namely
+ $[a]$ and $[b]$.
\end{enumerate}
\end{document}