hws/hw01.tex
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    16 \end{center}
    16 \end{center}
    17 
    17 
    18 \item {\bf (Optional)} Have a look at the crawler programs. 
    18 \item {\bf (Optional)} Have a look at the crawler programs. 
    19 Can you find a usage for them in your daily programming life?
    19 Can you find a usage for them in your daily programming life?
    20 
    20 
       
    21 \item Read the handout of the first lecture and make sure you
       
    22 understand the concepts of strings and languages. 
       
    23 
    21 \item In the context of the AFL-course, what is meant by the term \emph{language}?
    24 \item In the context of the AFL-course, what is meant by the term \emph{language}?
    22 
    25 
    23 \item Give the definition for regular expressions. What is the meaning of a 
    26 \item Give the definition for regular expressions. What is the meaning of a 
    24 regular expression?
    27 regular expression?
    25 
    28 
    27 Define the operation  of \emph{concatenating} two sets of strings.
    30 Define the operation  of \emph{concatenating} two sets of strings.
    28 
    31 
    29 \item How is the power of a language defined? (Hint: There are two rules, one for $\_\!\_^0$ and
    32 \item How is the power of a language defined? (Hint: There are two rules, one for $\_\!\_^0$ and
    30 one for $\_\!\_^{n+1}$.)
    33 one for $\_\!\_^{n+1}$.)
    31 
    34 
    32 \item Given the regular expressions $r_1 = \epsilon$ and $r_2 = \varnothing$ and $r_3 = a$.
       
    33 How many strings can the regular expressions $r_1^*$, $r_2^*$ and $r_3^*$ each match?
       
    34 
    35 
    35 \end{enumerate}
    36 \end{enumerate}
    36 
    37 
    37 \end{document}
    38 \end{document}
    38 
    39