\documentclass[compress, german, t]{beamer}

\usepackage[ngerman,english]{babel}
\uselanguage{German}
\languagepath{German}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage{helvet}
\usepackage{url}
\usepackage{listings}
\usepackage{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{automata}
\usetikzlibrary{calc}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{positioning}
\usepackage{tabu}

\usepackage{beamerthemeLEA2}

\newcommand{\N}       {\mathbb{N}}          % natürliche Zahlen
\newcommand{\Z}       {\mathbb{Z}}          % ganze Zahlen
\newcommand{\R}       {\mathbb{R}}          % reelle Zahlen
\newcommand{\Prob}    {\mathrm{P}}          % Wahrscheinlichkeit
\newcommand{\Oh}      {\mathcal{O}}         % O-Notation (Landau-Symbole)
\newcommand{\mycite}[1]{\textcolor{tumgreen}{[#1]}}

\tikzstyle{every edge} = [draw,very thick,->,>=latex]
\tikzstyle{every state} = [circle,thick,draw,fill=tumblue!10]
\tikzstyle{automaton} = [shorten >=1pt, node distance = 3cm, auto, bend angle=20, initial text=]
\tikzstyle{small} = [every node/.style={scale=0.5}, baseline=(current bounding box.north), font=\LARGE]

\title{Übung 2: Konversion RE $\rightarrow$ DFA}
\subtitle{Theoretische Informatik Sommersemester 2013}
\author{\href{mailto:markus.kaiser@in.tum.de}{Markus Kaiser}}

\begin{document}

\begin{frame}
    \titlepage
\end{frame}

\begin{frame}
    \setbeamercovered{dynamic}
    \frametitle{Reguläre Ausdrücke}

    \begin{definition}[Regulärer Ausdruck]
        \alert{Reguläre Ausdrücke} sind induktiv definiert
        \begin{itemize}
            \item \alert{$\emptyset$} ist ein regulärer Ausdruck
            \item \alert{$\epsilon$} ist ein regulärer Ausdruck
            \item Für alle $a \in \Sigma$ ist \alert{$a$} ein regulärer Ausdruck
            \item Sind $\alpha$ und $\beta$ reguläre Ausdrücke, dann auch
                \begin{description}
                    \item[Konkatenation] \alert{$\alpha\beta$}
                    \item[Veroderung] \alert{$\alpha \mid \beta$}
                    \item[Wiederholung] \alert{$\alpha^*$}
                \end{description}
        \end{itemize}
        Analoge Sprachdefinition, z.b. $L(\alpha\beta) = L(\alpha)L(\beta)$
    \end{definition}

    \begin{example}
        $\alpha = (0|1)^*00$ \hfill $L(\alpha) = \left\{x \mid x \text{ Binärzahl}, x \mod 4 = 0 \right\}$
    \end{example}
\end{frame}

\begin{frame}[c]
    \setbeamercovered{dynamic}
    \frametitle{Konversionen}

    \begin{center}
        \begin{tikzpicture}[node distance=2cm]
            \node (nfa) {NFA};
            \node (dfa) [left of=nfa] {DFA};
            \node (enfa) [right of=nfa] {$\epsilon$-NFA};
            \node (re) [below of=nfa] {RE};

            \draw [every edge, tumred] (nfa) -- (dfa);
            \draw [every edge, tumred] (enfa) -- (nfa);
            \draw [every edge] (dfa) -- (re);
            \draw [every edge] (nfa) -- (re);
            \draw [every edge, tumred] (re) -- (enfa);
        \end{tikzpicture}
    \end{center}
\end{frame}

\begin{frame}
    \setbeamercovered{dynamic}
    \frametitle{RE $\rightarrow$ $\epsilon$-NFA}

    \begin{block}{Idee (Kleene)}
        Für einen Ausdruck \alert{$\gamma$} wird rekursiv mit struktureller Induktion ein $\epsilon$-NFA konstruiert.
    \end{block}

    \begin{tabu} to \linewidth {XXX}
        \alert{$\gamma = \emptyset$} & \alert{$\gamma = \epsilon$} & \alert{$\gamma = a \in \Sigma$} \\
        \begin{tikzpicture}[automaton, small, baseline=(current bounding box.north)]
            \node[state, initial] () {};
        \end{tikzpicture} &

        \begin{tikzpicture}[automaton, small, baseline=(current bounding box.north)]
            \node[state, initial, accepting] () {};
        \end{tikzpicture} &

        \begin{tikzpicture}[automaton, small, baseline=(current bounding box.north)]
            \node[state, initial] (i) {};
            \node[state, accepting] (j) [right of=i] {};

            \draw[->] (i) edge node {$a$} (j);
        \end{tikzpicture} \\
        \vspace{2em}
        \alert{$\gamma = \alpha\beta$} \\
        \multicolumn3{c}{
            \begin{tikzpicture}[automaton, small]
                \draw[tumgreen, fill=tumgreen!20] (-0.3, 1) rectangle (1.8, -1);
                \node[tumgreen] () at (0.75, -1.2) {$N_\alpha$};

                \draw[tumgreen, fill=tumgreen!20] (3.7, 1) rectangle (5.8, -1);
                \node[tumgreen] () at (4.75, -1.2) {$N_\beta$};

                \node[state, initial] (i) at (0, 0) {};
                \node[state] (j) at (1.5, 0.5) {};
                \node[state] (k) at (1.5, -0.5) {};
                \node[state] (l) at (4, 0) {};
                \node[state, accepting] (m) at (5.5, 0) {};

                \draw[->] (j) edge node {$\epsilon$} (l);
                \draw[->] (k) edge node {$\epsilon$} (l);
            \end{tikzpicture}
        }\\
    \end{tabu}
\end{frame}

\begin{frame}
    \setbeamercovered{dynamic}
    \frametitle{RE $\rightarrow$ $\epsilon$-NFA}

    \begin{tabu} to \linewidth {X}
        \alert{$\gamma = \alpha \mid \beta$} \\
        \centering
        \begin{tikzpicture}[automaton, small]
            \draw[tumgreen, fill=tumgreen!20] (2, 1.5) rectangle (4.5, 0.5);
            \node[tumgreen] () at (3.25, 0.3) {$N_\alpha$};

            \draw[tumgreen, fill=tumgreen!20] (2, -0.5) rectangle (4.5, -1.5);
            \node[tumgreen] () at (3.25, -1.7) {$N_\beta$};

            \node[state, initial] (i) at (0, 0) {};

            \node[state] (j) at (2.5, 1) {};
            \node[state, accepting] (k) at (4, 1) {};
            \node[state] (l) at (2.5, -1) {};
            \node[state, accepting] (m) at (4, -1) {};

            \draw[->] (i) edge node {$\epsilon$} (j);
            \draw[->] (i) edge node {$\epsilon$} (l);
        \end{tikzpicture} \\
        \vfill

        \alert{$\gamma = \alpha^*$} \\
        \centering
        \begin{tikzpicture}[automaton, small, bend angle=70]
            \draw[tumgreen, fill=tumgreen!20] (2, 1) rectangle (4.5, -1);
            \node[tumgreen] () at (3.25, -1.2) {$N_\alpha$};

            \node[state, initial, accepting] (i) at (0, 0) {};

            \node[state] (j) at (2.5, 0) {};
            \node[state, accepting] (k) at (4, 0.5) {};
            \node[state, accepting] (m) at (4, -0.5) {};

            \draw[->] (i) edge node {$\epsilon$} (j);
            \draw[->] (k) edge [bend right] node {$\epsilon$} (j);
            \draw[->] (m) edge [bend left] node[above] {$\epsilon$} (j);
        \end{tikzpicture}
    \end{tabu}
\end{frame}

\begin{frame}
    \setbeamercovered{dynamic}
    \frametitle{$\epsilon$-NFA $\rightarrow$ NFA}

    \begin{block}{Idee}
        Entferne $\epsilon$-Kanten durch das Bilden von $\epsilon$-Hüllen.
        \begin{enumerate}
            \item<1-> Entferne \alert{unnötige Knoten}.
            \item<1,3-> Für jeden \alert{Pfad} der Form $\epsilon\ldots\epsilon \alert{a} \epsilon\ldots\epsilon$ verbinde Anfangs- und Endknoten mit einer \alert{$a$}-Kante.
            \item<1,4-> Entferne alle \alert{$\epsilon$-Kanten} und unerreichbare Knoten.
            \item<1,5-> Wurde das leere Wort akzeptiert mache den \alert{Anfangszustand} zum Endzustand.
        \end{enumerate}
    \end{block}

    \vfill

    \begin{tikzpicture}[automaton, bend angle=40, node distance=2.1cm]
        \useasboundingbox (-1.4,2) rectangle (9, -2);

        \node<-4>[state, initial] (q0) {$q_0$};
        \node[state] (q2) [right = 3.2cm of q0] {$q_2$};
        \node[state] (q3) [right of = q2] {$q_3$};
        \node[state, accepting] (q4) [right of = q3] {$q_4$};

        \draw[->] (q2) edge node {$0$} (q3);
        \draw[->] (q3) edge node {$1$} (q4);

        \draw<1-4>[->] (q3) edge [bend right] node [above] {$\epsilon$} (q2);
        \draw[->] (q4) edge [bend right] node [above] {$1$} (q3);
        \draw<1-4>[->] (q0) edge [bend right=20] node [below] {$\epsilon$} (q4);

        \node<1>[state] (q1) [right of = q0] {$q_1$};
        \draw<1>[->] (q0) edge node {$\epsilon$} (q1);
        \draw<1>[->] (q1) edge node {$1$} (q2);

        \node<2>[state, fill=tumred!20] (q1) [right of = q0] {$q_1$};
        \draw<2>[->, tumred] (q0) edge node {$\epsilon$} (q1);
        \draw<2>[->, tumred] (q1) edge node {$0$} (q2);
        \draw<2->[->, tumblue] (q0) edge [bend left] node {$0$} (q2);

        \draw<3,4,5>[->, tumred] (q0) edge [bend right=20] node [below] {$\epsilon$} (q4);
        \draw<3>[->, tumred] (q4) edge [bend right] node [above] {$1$} (q3);
        \draw<3,4>[->, tumred] (q3) edge [bend right] node [above] {$\epsilon$} (q2);
        \draw<3->[->, tumgreen] (q0) edge node {$1$} (q2);

        \draw<4->[->, tumgreen] (q2) edge [loop above] node [above] {$0$} (q2);
        \draw<4->[->, tumgreen] (q3) edge [loop above] node [above] {$0$} (q3);
        \draw<4->[->, tumgreen] (q0) edge [bend right=20] node [above] {$1$} (q3);
        \draw<4->[->, tumgreen] (q4) edge [bend right=70] node [above] {$1$} (q2);

        \node<5>[state, initial, accepting, fill=tumgreen!20] (q0) {$q_0$};

        \node<6->[state, initial, accepting] (q0) {$q_0$};
    \end{tikzpicture}
\end{frame}

\begin{frame}
    \setbeamercovered{dynamic}
    \frametitle{NFA $\rightarrow$ DFA}

    \begin{block}{Idee (Potenzmengenkonstruktion)}
        Konstruiere aus einem NFA $N = (Q, \Sigma, \delta, q_0, F)$ einen DFA $D = (P(Q), \Sigma, \overline{\delta}, \{q_0\}, F_M)$ mit Zuständen aus \alert{$P(Q)$}.

        \begin{itemize}
            \item $\overline{\delta}: \alert{P(Q)} \times \Sigma \mapsto P(Q)$ \\
                \[\overline{\delta}(S, a) := \bigcup_{q \in S} \delta(q, a)\]
            \item $F_M := \left\{S \subseteq Q \mid \alert{S \cap F} \neq \emptyset\right\}$
        \end{itemize}
    \end{block}

    \begin{tikzpicture}[automaton, bend angle=20, node distance=2.1cm]
        \useasboundingbox (-1.4,2) rectangle (9, -2);

        \node[state, initial] (q0) {$q_0$};
        \node[state, accepting] (q1) [right of = q0] {$q_1$};

        \draw[->] (q0) edge [loop above] node {$0,1$} (q0);
        \draw[->] (q0) edge node {$1$} (q1);

        \node<2->(sep) [right of = q1] {$\rightarrow$};

        \node<2->[state, initial, inner sep=1pt] (pq0) [right of = sep] {$q_{\{0\}}$};

        \node<3->[state, accepting, inner sep=0pt] (pq01) [right of = pq0] {$q_{\{0,1\}}$};
        \draw<3->[->] (pq0) edge [loop above] node {$0$} (pq0);
        \draw<3->[->] (pq0) edge [bend left] node {$1$} (pq01);

        \draw<4->[->] (pq01) edge [loop above] node {$1$} (pq01);
        \draw<4->[->] (pq01) edge [bend left] node {$0$} (pq0);

    \end{tikzpicture}
\end{frame}

\begin{frame}
    \setbeamercovered{dynamic}
    \frametitle{Produktautomat}
    \begin{theorem}
        Sind $M_1 = (Q_1, \Sigma, \delta_1, s_1, F_1)$ und $M_2 = (Q_2, \Sigma, \delta_2, s_2, F_2)$ DFAs, dann ist der \alert{Produkt-Automat}

        \begin{align*}
            M &:= (\alert{Q_1 \times Q_2}, \Sigma, \delta, (s_1, s_2), F_1 \times F_2) \\
            \delta\left( (q_1, q_2), a \right) &:= \left( \alert{\delta_1}(q_1, a), \alert{\delta_2}(q_2, a) \right)
        \end{align*}

        ein DFA, der $L(M_1) \cap L(M_2)$ akzeptiert.
    \end{theorem}

\end{frame}

\end{document}