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(*<*)
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theory Slides6
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imports "~~/src/HOL/Library/LaTeXsugar" "Nominal"
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begin
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declare [[show_question_marks = false]]
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notation (latex output)
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set ("_") and
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Cons ("_::/_" [66,65] 65)
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(*>*)
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text_raw {*
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\renewcommand{\slidecaption}{Shanghai, 12.~April 2011}
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\newcommand{\abst}[2]{#1.#2}% atom-abstraction
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\newcommand{\pair}[2]{\langle #1,#2\rangle} % pairing
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\newcommand{\susp}{{\boldsymbol{\cdot}}}% for suspensions
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\newcommand{\unit}{\langle\rangle}% unit
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\newcommand{\app}[2]{#1\,#2}% application
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\newcommand{\eqprob}{\mathrel{{\approx}?}}
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\newcommand{\freshprob}{\mathrel{\#?}}
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\newcommand{\redu}[1]{\stackrel{#1}{\Longrightarrow}}% reduction
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\newcommand{\id}{\varepsilon}% identity substitution
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\newcommand{\bl}[1]{\textcolor{blue}{#1}}
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\newcommand{\gr}[1]{\textcolor{gray}{#1}}
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\newcommand{\rd}[1]{\textcolor{red}{#1}}
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\newcommand{\ok}{\includegraphics[scale=0.07]{ok.png}}
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\newcommand{\notok}{\includegraphics[scale=0.07]{notok.png}}
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\newcommand{\largenotok}{\includegraphics[scale=1]{notok.png}}
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\renewcommand{\Huge}{\fontsize{61.92}{77}\selectfont}
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\newcommand{\veryHuge}{\fontsize{74.3}{93}\selectfont}
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\newcommand{\VeryHuge}{\fontsize{89.16}{112}\selectfont}
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\newcommand{\VERYHuge}{\fontsize{107}{134}\selectfont}
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\newcommand{\LL}{$\mathbb{L}\,$}
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\pgfdeclareradialshading{smallbluesphere}{\pgfpoint{0.5mm}{0.5mm}}%
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{rgb(0mm)=(0,0,0.9);
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rgb(0.9mm)=(0,0,0.7);
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rgb(1.3mm)=(0,0,0.5);
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rgb(1.4mm)=(1,1,1)}
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\def\myitemi{\begin{pgfpicture}{-1ex}{-0.55ex}{1ex}{1ex}
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\usebeamercolor[fg]{subitem projected}
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{\pgftransformscale{0.8}\pgftext{\normalsize\pgfuseshading{bigsphere}}}
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\pgftext{%
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\usebeamerfont*{subitem projected}}
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\end{pgfpicture}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}<1>[t]
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\frametitle{%
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\begin{tabular}{@ {\hspace{-3mm}}c@ {}}
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\\
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\LARGE Verifying a Regular Expression\\[-1mm]
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\LARGE Matcher and Formal Language\\[-1mm]
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\LARGE Theory\\[5mm]
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\end{tabular}}
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\begin{center}
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Christian Urban\\
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\small Technical University of Munich, Germany
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\end{center}
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\begin{center}
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\small joint work with Chunhan Wu and Xingyuan Zhang from the PLA
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University of Science and Technology in Nanjing
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\end{center}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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*}
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text_raw {*
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}<1->[c]
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\frametitle{My Background}
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\mbox{}\\[-10mm]
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\begin{itemize}
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\item My background is in theory and programming languages.\bigskip
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\pause
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\item But I am also a programmer with a \alert<2>{software system} of around 800 kloc
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(though I am responsible for only appr.~35 kloc),
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\item and I write papers.
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\end{itemize}
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\only<2>{
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\begin{textblock}{6}(6.5,11.5)
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\begin{tikzpicture}
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm]
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{\color{darkgray}
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\begin{minipage}{6.5cm}\raggedright
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\begin{tabular}[b]{@ {}p{4.5cm}c@ {}}
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\raggedright
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The software is a theorem prover, called {\bf Isabelle}.
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& \mbox{}\hspace{-5mm}\raisebox{-14mm}{\includegraphics[scale=0.28]{isabelle1.png}}
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\end{tabular}%
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\end{minipage}};
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\end{tikzpicture}
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\end{textblock}}
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\only<4>{
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\begin{textblock}{6}(3,11.5)
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\begin{tikzpicture}
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm]
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{\color{darkgray}
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\begin{minipage}{9.6cm}\raggedright
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So I can experience every day that writing error-free code is {\bf very, very hard}
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and that papers are also {\bf hard} to get correct.
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\end{minipage}};
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\end{tikzpicture}
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\end{textblock}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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*}
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text_raw {*
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}
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\frametitle{Getting Papers Correct}
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\begin{minipage}{1.1\textwidth}
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My work over the last 5 years.\\
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{\small (in the fields of programming languages, logic and lambda-calculi)}
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\end{minipage}\bigskip
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\only<1>{
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\mbox{}\\[15mm]
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\begin{center}
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\begin{tikzpicture}[node distance=0.5mm]
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\node at (-1.0,-0.3) (proof) [double arrow, fill=gray,text=white, minimum height=2cm]{\bf Proof};
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\node [left=of proof]{\Large\bf Specification};
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\node [right=of proof]{\Large\bf Code};
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\end{tikzpicture}
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\end{center}
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}
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\pause
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\begin{tabular}{c@ {\hspace{2mm}}c}
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\begin{tabular}{c}
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\includegraphics[scale=0.09]{harper.jpg}\\[-2mm]
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{\footnotesize Bob Harper}\\[-2.5mm]
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{\footnotesize (CMU)}
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\end{tabular}
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\begin{tabular}{c}
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\includegraphics[scale=0.31]{pfenning.jpg}\\[-2mm]
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{\footnotesize Frank Pfenning}\\[-2.5mm]
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{\footnotesize (CMU)}
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\end{tabular} &
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\begin{tabular}{p{6cm}}
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\raggedright\small
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\color{gray}{published a proof in ACM Transactions on Computational Logic (2005),
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$\sim$31pp}
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\end{tabular}\\
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\\[-4mm]
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\begin{tabular}{c}
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\includegraphics[scale=0.3]{appel.jpg}\\[-2mm]
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{\footnotesize Andrew Appel}\\[-2.5mm]
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{\footnotesize (Princeton)}
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\end{tabular} &
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\begin{tabular}{p{6cm}}
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\raggedright\small
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\color{gray}{relied on their proof in a safety critical system (proof carrying code)}
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\end{tabular}
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\end{tabular}\medskip
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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*}
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text_raw {*
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}
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\frametitle{Proof-Carrying Code}
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\begin{textblock}{10}(2.5,2.2)
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\begin{block}{Idea:}
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\begin{center}
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\begin{tikzpicture}
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\draw[help lines,cream] (0,0.2) grid (8,4);
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\draw[line width=1mm, red] (5.5,0.6) rectangle (7.5,4);
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\node[anchor=base] at (6.5,2.8)
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{\small\begin{tabular}{@ {}p{1.9cm}@ {}}\centering user needs to run untrusted code\end{tabular}};
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\draw[line width=1mm, red] (0.5,0.6) rectangle (2.5,4);
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\node[anchor=base] at (1.5,2.3)
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{\small\begin{tabular}{@ {}p{1.9cm}@ {}}\centering code developer/ web server/ Apple
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Store\end{tabular}};
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\onslide<4->{
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\draw[line width=1mm, red, fill=red] (5.5,0.6) rectangle (7.5,1.8);
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\node[anchor=base,white] at (6.5,1.1)
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{\small\begin{tabular}{@ {}p{1.9cm}@ {}}\bf\centering proof- checker\end{tabular}};}
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\node at (3.8,3.0) [single arrow, fill=red,text=white, minimum height=3cm]{\bf code};
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\onslide<3->{
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\node at (3.8,1.3) [single arrow, fill=red,text=white, minimum height=3cm]{\bf LF proof};
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\node at (3.8,1.9) {\small certificate};
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}
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\onslide<2>{\node at (4.0,1.3) [text=red]{\begin{tabular}{c}\bf Highly\\\bf Dangerous!\end{tabular}};}
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\end{tikzpicture}
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\end{center}
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\end{block}
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\end{textblock}
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\begin{textblock}{15}(2,12)
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\small
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\begin{itemize}
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\item<4-> Appel's checker is $\sim$2700 lines of code (1865 loc of\\ LF definitions;
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803 loc in C including 2 library functions)\\[-3mm]
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\item<5-> 167 loc in C implement a type-checker
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\end{itemize}
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\end{textblock}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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*}
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text {*
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\tikzstyle{every node}=[node distance=25mm,text height=1.5ex, text depth=.25ex]
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\tikzstyle{node1}=[rectangle, minimum size=10mm, rounded corners=3mm, very thick,
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draw=black!50, top color=white, bottom color=black!20]
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\tikzstyle{node2}=[rectangle, minimum size=12mm, rounded corners=3mm, very thick,
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draw=red!70, top color=white, bottom color=red!50!black!20]
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}<2->[squeeze]
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\frametitle{Type-Checking in LF}
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\begin{columns}
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\begin{column}{0.8\textwidth}
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\begin{textblock}{0}(1,2)
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\begin{tikzpicture}
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\matrix[ampersand replacement=\&,column sep=7mm, row sep=5mm]
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{ \&[-10mm]
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\node (def1) [node1] {\large\hspace{1mm}Spec\hspace{1mm}\mbox{}}; \&
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\node (proof1) [node1] {\large Proof}; \&
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\node (alg1) [node1] {\large\hspace{1mm}Alg\hspace{1mm}\mbox{}}; \\
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\onslide<4->{\node {\begin{tabular}{c}\small 1st\\[-2.5mm] \footnotesize solution\end{tabular}};} \&
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\onslide<4->{\node (def2) [node2] {\large Spec$^\text{+ex}$};} \&
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\onslide<4->{\node (proof2) [node1] {\large Proof};} \&
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\onslide<4->{\node (alg2) [node1] {\large\hspace{1mm}Alg\hspace{1mm}\mbox{}};} \\
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\onslide<5->{\node {\begin{tabular}{c}\small 2nd\\[-2.5mm] \footnotesize solution\end{tabular}};} \&
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\onslide<5->{\node (def3) [node1] {\large\hspace{1mm}Spec\hspace{1mm}\mbox{}};} \&
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\onslide<5->{\node (proof3) [node1] {\large Proof};} \&
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\onslide<5->{\node (alg3) [node2] {\large Alg$^\text{-ex}$};} \\
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\onslide<6->{\node {\begin{tabular}{c}\small 3rd\\[-2.5mm] \footnotesize solution\end{tabular}};} \&
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\onslide<6->{\node (def4) [node1] {\large\hspace{1mm}Spec\hspace{1mm}\mbox{}};} \&
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\onslide<6->{\node (proof4) [node2] {\large\hspace{1mm}Proof\hspace{1mm}};} \&
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\onslide<6->{\node (alg4) [node1] {\large\hspace{1mm}Alg\hspace{1mm}\mbox{}};} \\
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};
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\draw[->,black!50,line width=2mm] (proof1) -- (def1);
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\draw[->,black!50,line width=2mm] (proof1) -- (alg1);
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\onslide<4->{\draw[->,black!50,line width=2mm] (proof2) -- (def2);}
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\onslide<4->{\draw[->,black!50,line width=2mm] (proof2) -- (alg2);}
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\onslide<5->{\draw[->,black!50,line width=2mm] (proof3) -- (def3);}
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\onslide<5->{\draw[->,black!50,line width=2mm] (proof3) -- (alg3);}
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\onslide<6->{\draw[->,black!50,line width=2mm] (proof4) -- (def4);}
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\onslide<6->{\draw[->,black!50,line width=2mm] (proof4) -- (alg4);}
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\onslide<3->{\draw[white,line width=1mm] (1.1,3.2) -- (0.9,2.85) -- (1.1,2.35) -- (0.9,2.0);}
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\end{tikzpicture}
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\end{textblock}
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\end{column}
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\end{columns}
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\begin{textblock}{3}(12,3.6)
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\onslide<4->{
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\begin{tikzpicture}
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\node at (0,0) [single arrow, shape border rotate=270, fill=red,text=white]{2h};
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\end{tikzpicture}}
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\end{textblock}
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317 |
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\only<7->{
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\begin{textblock}{14}(0.6,12.8)
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\begin{block}{}
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\small Each time one needs to check $\sim$31pp~of informal paper proofs.
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You have to be able to keep definitions and proofs consistent.
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\end{block}
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\end{textblock}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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*}
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text_raw {*
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}<1->[c]
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\frametitle{Theorem Provers}
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337 |
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\begin{itemize}
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\item Theorem provers help with keeping large proofs consistent;
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make them modifiable.\medskip
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341 |
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\item They can ensure that all cases are covered.\medskip
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343 |
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\item Some reasoning can be automated.
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\end{itemize}\bigskip\pause
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\begin{minipage}{1.1\textwidth}
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Formal reasoning needs to be ``smooth''.\\
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{\small (ideally as close as possible to reasoning with ``pen-and-paper'')}
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\end{minipage}
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352 |
\only<2->{
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\begin{textblock}{3}(0.1,9.9)
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\begin{tikzpicture}
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\node at (0,0) [single arrow, shape border rotate=0, fill=red,text=red]{a};
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\end{tikzpicture}
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357 |
\end{textblock}}
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359 |
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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362 |
*}
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363 |
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364 |
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365 |
(*<*)
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366 |
atom_decl name
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367 |
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368 |
nominal_datatype lam =
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369 |
Var "name"
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370 |
| App "lam" "lam"
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371 |
| Lam "\<guillemotleft>name\<guillemotright>lam" ("Lam [_]._" [100,100] 100)
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372 |
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373 |
nominal_primrec
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374 |
subst :: "lam \<Rightarrow> name \<Rightarrow> lam \<Rightarrow> lam" ("_[_::=_]")
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375 |
where
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376 |
"(Var x)[y::=s] = (if x=y then s else (Var x))"
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377 |
| "(App t\<^isub>1 t\<^isub>2)[y::=s] = App (t\<^isub>1[y::=s]) (t\<^isub>2[y::=s])"
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378 |
| "x\<sharp>(y,s) \<Longrightarrow> (Lam [x].t)[y::=s] = Lam [x].(t[y::=s])"
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379 |
apply(finite_guess)+
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380 |
apply(rule TrueI)+
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381 |
apply(simp add: abs_fresh)
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382 |
apply(fresh_guess)+
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383 |
done
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384 |
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385 |
lemma subst_eqvt[eqvt]:
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386 |
fixes pi::"name prm"
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387 |
shows "pi\<bullet>(t1[x::=t2]) = (pi\<bullet>t1)[(pi\<bullet>x)::=(pi\<bullet>t2)]"
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388 |
by (nominal_induct t1 avoiding: x t2 rule: lam.strong_induct)
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389 |
(auto simp add: perm_bij fresh_atm fresh_bij)
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390 |
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|
391 |
lemma fresh_fact:
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392 |
fixes z::"name"
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393 |
shows "\<lbrakk>z\<sharp>s; (z=y \<or> z\<sharp>t)\<rbrakk> \<Longrightarrow> z\<sharp>t[y::=s]"
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|
394 |
by (nominal_induct t avoiding: z y s rule: lam.strong_induct)
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|
395 |
(auto simp add: abs_fresh fresh_prod fresh_atm)
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396 |
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397 |
lemma forget:
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|
398 |
assumes asm: "x\<sharp>L"
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399 |
shows "L[x::=P] = L"
|
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|
400 |
using asm
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|
401 |
by (nominal_induct L avoiding: x P rule: lam.strong_induct)
|
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|
402 |
(auto simp add: abs_fresh fresh_atm)
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|
403 |
(*>*)
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2762
|
404 |
|
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2764
|
405 |
text_raw {*
|
|
|
406 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
407 |
\mode<presentation>{
|
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|
408 |
\begin{frame}
|
|
|
409 |
|
|
|
410 |
\begin{textblock}{16}(1,1)
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|
411 |
\renewcommand{\isasymbullet}{$\cdot$}
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|
412 |
\tiny\color{black}
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|
413 |
*}
|
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|
414 |
lemma substitution_lemma_not_to_be_tried_at_home:
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|
415 |
assumes asm: "x\<noteq>y" "x\<sharp>L"
|
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|
416 |
shows "M[x::=N][y::=L] = M[y::=L][x::=N[y::=L]]"
|
|
|
417 |
using asm
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|
|
418 |
proof (induct M arbitrary: x y N L rule: lam.induct)
|
|
|
419 |
case (Lam z M1)
|
|
|
420 |
have ih: "\<And>x y N L. \<lbrakk>x\<noteq>y; x\<sharp>L\<rbrakk> \<Longrightarrow> M1[x::=N][y::=L] = M1[y::=L][x::=N[y::=L]]" by fact
|
|
|
421 |
have "x\<noteq>y" by fact
|
|
|
422 |
have "x\<sharp>L" by fact
|
|
|
423 |
obtain z'::"name" where fc: "z'\<sharp>(x,y,z,M1,N,L)" by (rule exists_fresh) (auto simp add: fs_name1)
|
|
|
424 |
have eq: "Lam [z'].([(z',z)]\<bullet>M1) = Lam [z].M1" using fc
|
|
|
425 |
by (auto simp add: lam.inject alpha fresh_prod fresh_atm)
|
|
|
426 |
have fc': "z'\<sharp>N[y::=L]" using fc by (simp add: fresh_fact fresh_prod)
|
|
|
427 |
have "([(z',z)]\<bullet>x) \<noteq> ([(z',z)]\<bullet>y)" using `x\<noteq>y` by (auto simp add: calc_atm)
|
|
|
428 |
moreover
|
|
|
429 |
have "([(z',z)]\<bullet>x)\<sharp>([(z',z)]\<bullet>L)" using `x\<sharp>L` by (simp add: fresh_bij)
|
|
|
430 |
ultimately
|
|
|
431 |
have "M1[([(z',z)]\<bullet>x)::=([(z',z)]\<bullet>N)][([(z',z)]\<bullet>y)::=([(z',z)]\<bullet>L)]
|
|
|
432 |
= M1[([(z',z)]\<bullet>y)::=([(z',z)]\<bullet>L)][([(z',z)]\<bullet>x)::=([(z',z)]\<bullet>N)[([(z',z)]\<bullet>y)::=([(z',z)]\<bullet>L)]]"
|
|
|
433 |
using ih by simp
|
|
|
434 |
then have "[(z',z)]\<bullet>(M1[([(z',z)]\<bullet>x)::=([(z',z)]\<bullet>N)][([(z',z)]\<bullet>y)::=([(z',z)]\<bullet>L)]
|
|
|
435 |
= M1[([(z',z)]\<bullet>y)::=([(z',z)]\<bullet>L)][([(z',z)]\<bullet>x)::=([(z',z)]\<bullet>N)[([(z',z)]\<bullet>y)::=([(z',z)]\<bullet>L)]])"
|
|
|
436 |
by (simp add: perm_bool)
|
|
|
437 |
then have ih': "([(z',z)]\<bullet>M1)[x::=N][y::=L] = ([(z',z)]\<bullet>M1)[y::=L][x::=N[y::=L]]"
|
|
|
438 |
by (simp add: eqvts perm_swap)
|
|
|
439 |
show "(Lam [z].M1)[x::=N][y::=L] = (Lam [z].M1)[y::=L][x::=N[y::=L]]" (is "?LHS=?RHS")
|
|
|
440 |
proof -
|
|
|
441 |
have "?LHS = (Lam [z'].([(z',z)]\<bullet>M1))[x::=N][y::=L]" using eq by simp
|
|
|
442 |
also have "\<dots> = Lam [z'].(([(z',z)]\<bullet>M1)[x::=N][y::=L])" using fc by (simp add: fresh_prod)
|
|
|
443 |
also from ih have "\<dots> = Lam [z'].(([(z',z)]\<bullet>M1)[y::=L][x::=N[y::=L]])" sorry
|
|
|
444 |
also have "\<dots> = (Lam [z'].([(z',z)]\<bullet>M1))[y::=L][x::=N[y::=L]]" using fc fc' by (simp add: fresh_prod)
|
|
|
445 |
also have "\<dots> = ?RHS" using eq by simp
|
|
|
446 |
finally show "?LHS = ?RHS" .
|
|
|
447 |
qed
|
|
|
448 |
qed (auto simp add: forget)
|
|
|
449 |
text_raw {*
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|
|
450 |
\end{textblock}
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|
451 |
\mbox{}
|
|
|
452 |
|
|
|
453 |
\only<2->{
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|
|
454 |
\begin{textblock}{11.5}(4,2.3)
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|
|
455 |
\begin{minipage}{9.3cm}
|
|
|
456 |
\begin{block}{}\footnotesize
|
|
|
457 |
*}
|
|
|
458 |
lemma substitution_lemma\<iota>:
|
|
|
459 |
assumes asm: "x \<noteq> y" "x \<sharp> L"
|
|
|
460 |
shows "M[x::=N][y::=L] = M[y::=L][x::=N[y::=L]]"
|
|
|
461 |
using asm
|
|
|
462 |
by (nominal_induct M avoiding: x y N L rule: lam.strong_induct)
|
|
|
463 |
(auto simp add: forget fresh_fact)
|
|
|
464 |
text_raw {*
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|
|
465 |
\end{block}
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|
466 |
\end{minipage}
|
|
|
467 |
\end{textblock}}
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|
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|
468 |
\end{frame}}
|
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|
469 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
470 |
*}
|
|
|
471 |
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472 |
text_raw {*
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|
|
473 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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|
|
474 |
\mode<presentation>{
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|
|
475 |
\begin{frame}<1>[c]
|
|
2764
|
476 |
\frametitle{Getting Programs Correct}
|
|
|
477 |
|
|
|
478 |
\begin{center}
|
|
|
479 |
\begin{tikzpicture}[node distance=0.5mm]
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|
480 |
\node at (-1.0,-0.3) (proof) [double arrow, fill=gray,text=white, minimum height=2cm]{\bf Proof};
|
|
|
481 |
\node [left=of proof]{\Large\bf Specification};
|
|
|
482 |
\node [right=of proof]{\Large\bf Code};
|
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|
483 |
\end{tikzpicture}
|
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|
484 |
\end{center}
|
|
|
485 |
|
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|
486 |
|
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|
487 |
|
|
|
488 |
\end{frame}}
|
|
|
489 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
490 |
*}
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491 |
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|
492 |
text_raw {*
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|
493 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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|
494 |
\mode<presentation>{
|
|
|
495 |
\begin{frame}<1->[t]
|
|
|
496 |
\frametitle{Regular Expressions}
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|
497 |
|
|
2764
|
498 |
\begin{textblock}{6}(2,4)
|
|
|
499 |
\begin{tabular}{@ {}rrl}
|
|
|
500 |
\bl{r} & \bl{$::=$} & \bl{$\varnothing$}\\
|
|
|
501 |
& \bl{$\mid$} & \bl{[]}\\
|
|
|
502 |
& \bl{$\mid$} & \bl{c}\\
|
|
|
503 |
& \bl{$\mid$} & \bl{r$_1$ + r$_2$}\\
|
|
|
504 |
& \bl{$\mid$} & \bl{r$_1$ $\cdot$ r$_2$}\\
|
|
|
505 |
& \bl{$\mid$} & \bl{r$^*$}\\
|
|
|
506 |
\end{tabular}
|
|
|
507 |
\end{textblock}
|
|
|
508 |
|
|
|
509 |
\begin{textblock}{6}(8,3.5)
|
|
|
510 |
\includegraphics[scale=0.35]{Screen1.png}
|
|
|
511 |
\end{textblock}
|
|
2762
|
512 |
|
|
2764
|
513 |
\begin{textblock}{6}(10.2,2.8)
|
|
|
514 |
\footnotesize Isabelle:
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|
|
515 |
\end{textblock}
|
|
|
516 |
|
|
|
517 |
\only<2>{
|
|
|
518 |
\begin{textblock}{9}(3.6,11.8)
|
|
|
519 |
\bl{matches r s $\;\Longrightarrow\;$ true $\vee$ false}\\[3.5mm]
|
|
|
520 |
|
|
|
521 |
\hspace{10mm}\begin{tikzpicture}
|
|
|
522 |
\coordinate (m1) at (0.4,1);
|
|
|
523 |
\draw (0,0.3) node (m2) {\small\color{gray}rexp};
|
|
|
524 |
\path[overlay, ->, line width = 0.5mm, shorten <=-1mm, draw = gray] (m2) edge (m1);
|
|
|
525 |
|
|
|
526 |
\coordinate (s1) at (0.81,1);
|
|
|
527 |
\draw (1.3,0.3) node (s2) {\small\color{gray} string};
|
|
|
528 |
\path[overlay, ->, line width = 0.5mm, shorten <=-1mm, draw = gray] (s2) edge (s1);
|
|
|
529 |
\end{tikzpicture}
|
|
|
530 |
\end{textblock}}
|
|
|
531 |
|
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|
532 |
|
|
2762
|
533 |
|
|
|
534 |
\end{frame}}
|
|
|
535 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
536 |
*}
|
|
|
537 |
|
|
|
538 |
text_raw {*
|
|
|
539 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
540 |
\mode<presentation>{
|
|
2764
|
541 |
\begin{frame}<1->[t]
|
|
|
542 |
\frametitle{Specification}
|
|
|
543 |
|
|
|
544 |
\small
|
|
|
545 |
\begin{textblock}{6}(0,3.5)
|
|
|
546 |
\begin{tabular}{r@ {\hspace{0.5mm}}r@ {\hspace{1.5mm}}c@ {\hspace{1.5mm}}l}
|
|
|
547 |
\multicolumn{4}{c}{rexp $\Rightarrow$ set of strings}\bigskip\\
|
|
|
548 |
&\bl{\LL ($\varnothing$)} & \bl{$\dn$} & \bl{$\varnothing$}\\
|
|
|
549 |
&\bl{\LL ([])} & \bl{$\dn$} & \bl{\{[]\}}\\
|
|
|
550 |
&\bl{\LL (c)} & \bl{$\dn$} & \bl{\{c\}}\\
|
|
|
551 |
&\bl{\LL (r$_1$ + r$_2$)} & \bl{$\dn$} & \bl{\LL (r$_1$) $\cup$ \LL (r$_2$)}\\
|
|
|
552 |
\rd{$\Rightarrow$} &\bl{\LL (r$_1$ $\cdot$ r$_2$)} & \bl{$\dn$} & \bl{\LL (r$_1$) ;; \LL (r$_2$)}\\
|
|
|
553 |
\rd{$\Rightarrow$} &\bl{\LL (r$^*$)} & \bl{$\dn$} & \bl{(\LL (r))$^\star$}\\
|
|
|
554 |
\end{tabular}
|
|
|
555 |
\end{textblock}
|
|
|
556 |
|
|
|
557 |
\begin{textblock}{9}(7.3,3)
|
|
|
558 |
{\mbox{}\hspace{2cm}\footnotesize Isabelle:\smallskip}
|
|
|
559 |
\includegraphics[scale=0.325]{Screen3.png}
|
|
|
560 |
\end{textblock}
|
|
|
561 |
|
|
|
562 |
\end{frame}}
|
|
|
563 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
564 |
*}
|
|
|
565 |
|
|
|
566 |
|
|
|
567 |
text_raw {*
|
|
|
568 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
569 |
\mode<presentation>{
|
|
|
570 |
\begin{frame}<1->[t]
|
|
|
571 |
\frametitle{Version 1}
|
|
|
572 |
\small
|
|
|
573 |
\mbox{}\\[-8mm]\mbox{}
|
|
|
574 |
|
|
|
575 |
\begin{center}\def\arraystretch{1.05}
|
|
|
576 |
\begin{tabular}{@ {\hspace{-5mm}}l@ {\hspace{2.5mm}}c@ {\hspace{2.5mm}}l@ {}}
|
|
|
577 |
\bl{match [] []} & \bl{$=$} & \bl{true}\\
|
|
|
578 |
\bl{match [] (c::s)} & \bl{$=$} & \bl{false}\\
|
|
|
579 |
\bl{match ($\varnothing$::rs) s} & \bl{$=$} & \bl{false}\\
|
|
|
580 |
\bl{match ([]::rs) s} & \bl{$=$} & \bl{match rs s}\\
|
|
|
581 |
\bl{match (c::rs) []} & \bl{$=$} & \bl{false}\\
|
|
|
582 |
\bl{match (c::rs) (d::s)} & \bl{$=$} & \bl{if c = d then match rs s else false}\\
|
|
|
583 |
\bl{match (r$_1$ + r$_2$::rs) s} & \bl{$=$} & \bl{match (r$_1$::rs) s $\vee$ match (r$_2$::rs) s}\\
|
|
|
584 |
\bl{match (r$_1$ $\cdot$ r$_2$::rs) s} & \bl{$=$} & \bl{match (r$_1$::r$_2$::rs) s}\\
|
|
|
585 |
\bl{match (r$^*$::rs) s} & \bl{$=$} & \bl{match rs s $\vee$ match (r::r$^*$::rs) s}\\
|
|
|
586 |
\end{tabular}
|
|
|
587 |
\end{center}
|
|
|
588 |
|
|
|
589 |
\begin{textblock}{9}(0.2,1.6)
|
|
|
590 |
\hspace{10mm}\begin{tikzpicture}
|
|
|
591 |
\coordinate (m1) at (0.44,-0.5);
|
|
|
592 |
\draw (0,0.3) node (m2) {\small\color{gray}\mbox{}\hspace{-9mm}list of rexps};
|
|
|
593 |
\path[overlay, ->, line width = 0.5mm, shorten <=-1mm, draw = gray] (m2) edge (m1);
|
|
|
594 |
|
|
|
595 |
\coordinate (s1) at (0.86,-0.5);
|
|
|
596 |
\draw (1.5,0.3) node (s2) {\small\color{gray} string};
|
|
|
597 |
\path[overlay, ->, line width = 0.5mm, shorten <=-1mm, draw = gray] (s2) edge (s1);
|
|
|
598 |
\end{tikzpicture}
|
|
|
599 |
\end{textblock}
|
|
|
600 |
|
|
|
601 |
\begin{textblock}{9}(2.8,11.8)
|
|
|
602 |
\bl{matches$_1$ r s $\;=\;$ match [r] s}
|
|
|
603 |
\end{textblock}
|
|
|
604 |
|
|
|
605 |
\end{frame}}
|
|
|
606 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
607 |
*}
|
|
2762
|
608 |
|
|
2764
|
609 |
text_raw {*
|
|
|
610 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
611 |
\mode<presentation>{
|
|
|
612 |
\begin{frame}<1->[c]
|
|
|
613 |
\frametitle{Testing}
|
|
|
614 |
|
|
|
615 |
\small
|
|
|
616 |
Every good programmer should do thourough tests:
|
|
|
617 |
|
|
|
618 |
\begin{center}
|
|
|
619 |
\begin{tabular}{@ {\hspace{-20mm}}lcl}
|
|
|
620 |
\bl{matches (a$\cdot$b)$^*\;$ []} & \bl{$\mapsto$} & \bl{true}\\
|
|
|
621 |
\bl{matches (a$\cdot$b)$^*\;$ ab} & \bl{$\mapsto$} & \bl{true}\\
|
|
|
622 |
\bl{matches (a$\cdot$b)$^*\;$ aba} & \bl{$\mapsto$} & \bl{false}\\
|
|
|
623 |
\bl{matches (a$\cdot$b)$^*\;$ abab} & \bl{$\mapsto$} & \bl{true}\\
|
|
|
624 |
\bl{matches (a$\cdot$b)$^*\;$ abaa} & \bl{$\mapsto$} & \bl{false}\medskip\\
|
|
|
625 |
\onslide<2->{\bl{matches x$\cdot$(0$|$1)$^*\;$ x} & \bl{$\mapsto$} & \bl{true}}\\
|
|
|
626 |
\onslide<2->{\bl{matches x$\cdot$(0$|$1)$^*\;$ x0} & \bl{$\mapsto$} & \bl{true}}\\
|
|
|
627 |
\onslide<2->{\bl{matches x$\cdot$(0$|$1)$^*\;$ x3} & \bl{$\mapsto$} & \bl{false}}
|
|
|
628 |
\end{tabular}
|
|
|
629 |
\end{center}
|
|
|
630 |
|
|
|
631 |
\onslide<3->
|
|
|
632 |
{looks OK \ldots let's ship it to customers\hspace{5mm}
|
|
|
633 |
\raisebox{-5mm}{\includegraphics[scale=0.05]{sun.png}}}
|
|
|
634 |
|
|
|
635 |
\end{frame}}
|
|
|
636 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
637 |
*}
|
|
|
638 |
|
|
|
639 |
text_raw {*
|
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|
640 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
641 |
\mode<presentation>{
|
|
|
642 |
\begin{frame}<1->[c]
|
|
|
643 |
\frametitle{Version 1}
|
|
|
644 |
|
|
|
645 |
\only<1->{Several hours later\ldots}\pause
|
|
|
646 |
|
|
|
647 |
|
|
|
648 |
\begin{center}
|
|
|
649 |
\begin{tabular}{@ {\hspace{0mm}}lcl}
|
|
|
650 |
\bl{matches$_1$ []$^*$ s} & \bl{$\mapsto$} & loops\\
|
|
|
651 |
\onslide<4->{\bl{matches$_1$ ([] + \ldots)$^*$ s} & \bl{$\mapsto$} & loops\\}
|
|
|
652 |
\end{tabular}
|
|
|
653 |
\end{center}
|
|
|
654 |
|
|
|
655 |
\small
|
|
|
656 |
\onslide<3->{
|
|
|
657 |
\begin{center}
|
|
|
658 |
\begin{tabular}{@ {}l@ {\hspace{2mm}}c@ {\hspace{2mm}}l@ {}}
|
|
|
659 |
\ldots\\
|
|
|
660 |
\bl{match ([]::rs) s} & \bl{$=$} & \bl{match rs s}\\
|
|
|
661 |
\ldots\\
|
|
|
662 |
\bl{match (r$^*$::rs) s} & \bl{$=$} & \bl{match rs s $\vee$ match (r::r$^*$::rs) s}\\
|
|
|
663 |
\end{tabular}
|
|
|
664 |
\end{center}}
|
|
|
665 |
|
|
|
666 |
|
|
|
667 |
\end{frame}}
|
|
|
668 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
669 |
*}
|
|
|
670 |
|
|
|
671 |
|
|
|
672 |
text_raw {*
|
|
|
673 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
674 |
\mode<presentation>{
|
|
|
675 |
\begin{frame}<1->[t]
|
|
|
676 |
\frametitle{Testing}
|
|
2762
|
677 |
|
|
|
678 |
\begin{itemize}
|
|
2764
|
679 |
\item While testing is an important part in the process of programming development\pause
|
|
|
680 |
|
|
|
681 |
\item We can only test a {\bf finite} amount of examples.\bigskip\pause
|
|
2762
|
682 |
|
|
2764
|
683 |
\begin{center}
|
|
|
684 |
\colorbox{cream}
|
|
|
685 |
{\gr{\begin{minipage}{10cm}
|
|
|
686 |
``Testing can only show the presence of errors, never their
|
|
|
687 |
absence'' (Edsger W.~Dijkstra)
|
|
|
688 |
\end{minipage}}}
|
|
|
689 |
\end{center}\bigskip\pause
|
|
|
690 |
|
|
|
691 |
\item In a theorem prover we can establish properties that apply to
|
|
|
692 |
{\bf all} input and {\bf all} output.\pause
|
|
|
693 |
|
|
2762
|
694 |
\end{itemize}
|
|
|
695 |
|
|
|
696 |
\end{frame}}
|
|
|
697 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
698 |
*}
|
|
|
699 |
|
|
|
700 |
|
|
|
701 |
text_raw {*
|
|
|
702 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
703 |
\mode<presentation>{
|
|
2764
|
704 |
\begin{frame}<1->[t]
|
|
|
705 |
\frametitle{Version 2}
|
|
|
706 |
\mbox{}\\[-14mm]\mbox{}
|
|
|
707 |
|
|
|
708 |
\small
|
|
|
709 |
\begin{tabular}{@ {}l@ {\hspace{2mm}}c@ {\hspace{2mm}}ll@ {}}
|
|
|
710 |
\bl{nullable ($\varnothing$)} & \bl{$=$} & \bl{false} &\\
|
|
|
711 |
\bl{nullable ([])} & \bl{$=$} & \bl{true} &\\
|
|
|
712 |
\bl{nullable (c)} & \bl{$=$} & \bl{false} &\\
|
|
|
713 |
\bl{nullable (r$_1$ + r$_2$)} & \bl{$=$} & \bl{nullable r$_1$ $\vee$ nullable r$_2$} & \\
|
|
|
714 |
\bl{nullable (r$_1$ $\cdot$ r$_2$)} & \bl{$=$} & \bl{nullable r$_1$ $\wedge$ nullable r$_2$} & \\
|
|
|
715 |
\bl{nullable (r$^*$)} & \bl{$=$} & \bl{true} & \\
|
|
|
716 |
\end{tabular}\medskip
|
|
|
717 |
|
|
|
718 |
\begin{tabular}{@ {}l@ {\hspace{2mm}}c@ {\hspace{2mm}}l@ {\hspace{-10mm}}l@ {}}
|
|
|
719 |
\bl{der c ($\varnothing$)} & \bl{$=$} & \bl{$\varnothing$} & \\
|
|
|
720 |
\bl{der c ([])} & \bl{$=$} & \bl{$\varnothing$} & \\
|
|
|
721 |
\bl{der c (d)} & \bl{$=$} & \bl{if c = d then [] else $\varnothing$} & \\
|
|
|
722 |
\bl{der c (r$_1$ + r$_2$)} & \bl{$=$} & \bl{(der c r$_1$) + (der c r$_2$)} & \\
|
|
|
723 |
\bl{der c (r$_1$ $\cdot$ r$_2$)} & \bl{$=$} & \bl{((der c r$_1$) $\cdot$ r$_2$)} & \\
|
|
|
724 |
& & \bl{\;\;+ (if nullable r$_1$ then der c r$_2$ else $\varnothing$)}\\
|
|
|
725 |
\bl{der c (r$^*$)} & \bl{$=$} & \bl{(der c r) $\cdot$ r$^*$} &\smallskip\\
|
|
2762
|
726 |
|
|
2764
|
727 |
\bl{derivative r []} & \bl{$=$} & \bl{r} & \\
|
|
|
728 |
\bl{derivative r (c::s)} & \bl{$=$} & \bl{derivative (der c r) s} & \\
|
|
|
729 |
\end{tabular}\medskip
|
|
|
730 |
|
|
|
731 |
\bl{matches$_2$ r s $=$ nullable (derivative r s)}
|
|
|
732 |
|
|
|
733 |
\begin{textblock}{6}(9.5,0.9)
|
|
|
734 |
\begin{flushright}
|
|
|
735 |
\color{gray}``if r matches []''
|
|
|
736 |
\end{flushright}
|
|
|
737 |
\end{textblock}
|
|
|
738 |
|
|
|
739 |
\begin{textblock}{6}(9.5,6.18)
|
|
|
740 |
\begin{flushright}
|
|
|
741 |
\color{gray}``derivative for a char''
|
|
|
742 |
\end{flushright}
|
|
|
743 |
\end{textblock}
|
|
|
744 |
|
|
|
745 |
\begin{textblock}{6}(9.5,12.1)
|
|
|
746 |
\begin{flushright}
|
|
|
747 |
\color{gray}``deriv.~for a string''
|
|
|
748 |
\end{flushright}
|
|
|
749 |
\end{textblock}
|
|
|
750 |
|
|
|
751 |
\begin{textblock}{6}(9.5,13.98)
|
|
|
752 |
\begin{flushright}
|
|
|
753 |
\color{gray}``main''
|
|
|
754 |
\end{flushright}
|
|
|
755 |
\end{textblock}
|
|
2762
|
756 |
|
|
|
757 |
\end{frame}}
|
|
|
758 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
759 |
*}
|
|
|
760 |
|
|
|
761 |
text_raw {*
|
|
|
762 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
763 |
\mode<presentation>{
|
|
2764
|
764 |
\begin{frame}<1->[t]
|
|
|
765 |
\frametitle{Is the Matcher Error-Free?}
|
|
2762
|
766 |
|
|
2764
|
767 |
We expect that
|
|
2762
|
768 |
|
|
2764
|
769 |
\begin{center}
|
|
|
770 |
\begin{tabular}{lcl}
|
|
|
771 |
\bl{matches$_2$ r s = true} & \only<1>{\rd{$\Longrightarrow\,\,$}}\only<2>{\rd{$\Longleftarrow\,\,$}}%
|
|
|
772 |
\only<3->{\rd{$\Longleftrightarrow$}} & \bl{s $\in$ \LL(r)}\\
|
|
|
773 |
\bl{matches$_2$ r s = false} & \only<1>{\rd{$\Longrightarrow\,\,$}}\only<2>{\rd{$\Longleftarrow\,\,$}}%
|
|
|
774 |
\only<3->{\rd{$\Longleftrightarrow$}} & \bl{s $\notin$ \LL(r)}\\
|
|
|
775 |
\end{tabular}
|
|
|
776 |
\end{center}
|
|
|
777 |
\pause\pause\bigskip
|
|
|
778 |
By \alert<4->{induction}, we can {\bf prove} these properties.\bigskip
|
|
|
779 |
|
|
|
780 |
\begin{tabular}{lrcl}
|
|
|
781 |
Lemmas: & \bl{nullable (r)} & \bl{$\Longleftrightarrow$} & \bl{[] $\in$ \LL (r)}\\
|
|
|
782 |
& \bl{s $\in$ \LL (der c r)} & \bl{$\Longleftrightarrow$} & \bl{(c::s) $\in$ \LL (r)}\\
|
|
|
783 |
\end{tabular}
|
|
2762
|
784 |
|
|
2764
|
785 |
\only<4->{
|
|
|
786 |
\begin{textblock}{3}(0.9,4.5)
|
|
|
787 |
\rd{\huge$\forall$\large{}r s.}
|
|
2762
|
788 |
\end{textblock}}
|
|
|
789 |
\end{frame}}
|
|
|
790 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
791 |
*}
|
|
|
792 |
|
|
|
793 |
text_raw {*
|
|
|
794 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
795 |
\mode<presentation>{
|
|
|
796 |
\begin{frame}<1>[c]
|
|
|
797 |
\frametitle{
|
|
|
798 |
\begin{tabular}{c}
|
|
|
799 |
\mbox{}\\[23mm]
|
|
|
800 |
\LARGE Demo
|
|
|
801 |
\end{tabular}}
|
|
|
802 |
|
|
|
803 |
\end{frame}}
|
|
|
804 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
805 |
*}
|
|
|
806 |
|
|
|
807 |
|
|
|
808 |
text_raw {*
|
|
|
809 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
810 |
\mode<presentation>{
|
|
2764
|
811 |
\begin{frame}<1->[t]
|
|
|
812 |
|
|
|
813 |
\mbox{}\\[-2mm]
|
|
|
814 |
|
|
|
815 |
\small
|
|
|
816 |
\begin{tabular}{@ {}l@ {\hspace{2mm}}c@ {\hspace{2mm}}ll@ {}}
|
|
|
817 |
\bl{nullable (NULL)} & \bl{$=$} & \bl{false} &\\
|
|
|
818 |
\bl{nullable (EMPTY)} & \bl{$=$} & \bl{true} &\\
|
|
|
819 |
\bl{nullable (CHR c)} & \bl{$=$} & \bl{false} &\\
|
|
|
820 |
\bl{nullable (ALT r$_1$ r$_2$)} & \bl{$=$} & \bl{(nullable r$_1$) orelse (nullable r$_2$)} & \\
|
|
|
821 |
\bl{nullable (SEQ r$_1$ r$_2$)} & \bl{$=$} & \bl{(nullable r$_1$) andalso (nullable r$_2$)} & \\
|
|
|
822 |
\bl{nullable (STAR r)} & \bl{$=$} & \bl{true} & \\
|
|
|
823 |
\end{tabular}\medskip
|
|
|
824 |
|
|
|
825 |
\begin{tabular}{@ {}l@ {\hspace{2mm}}c@ {\hspace{2mm}}l@ {\hspace{-10mm}}l@ {}}
|
|
|
826 |
\bl{der c (NULL)} & \bl{$=$} & \bl{NULL} & \\
|
|
|
827 |
\bl{der c (EMPTY)} & \bl{$=$} & \bl{NULL} & \\
|
|
|
828 |
\bl{der c (CHR d)} & \bl{$=$} & \bl{if c=d then EMPTY else NULL} & \\
|
|
|
829 |
\bl{der c (ALT r$_1$ r$_2$)} & \bl{$=$} & \bl{ALT (der c r$_1$) (der c r$_2$)} & \\
|
|
|
830 |
\bl{der c (SEQ r$_1$ r$_2$)} & \bl{$=$} & \bl{ALT (SEQ (der c r$_1$) r$_2$)} & \\
|
|
|
831 |
& & \bl{\phantom{ALT} (if nullable r$_1$ then der c r$_2$ else NULL)}\\
|
|
|
832 |
\bl{der c (STAR r)} & \bl{$=$} & \bl{SEQ (der c r) (STAR r)} &\smallskip\\
|
|
|
833 |
|
|
|
834 |
\bl{derivative r []} & \bl{$=$} & \bl{r} & \\
|
|
|
835 |
\bl{derivative r (c::s)} & \bl{$=$} & \bl{derivative (der c r) s} & \\
|
|
|
836 |
\end{tabular}\medskip
|
|
|
837 |
|
|
|
838 |
\bl{matches r s $=$ nullable (derivative r s)}
|
|
|
839 |
|
|
|
840 |
\only<2>{
|
|
|
841 |
\begin{textblock}{8}(1.5,4)
|
|
|
842 |
\includegraphics[scale=0.3]{approved.png}
|
|
|
843 |
\end{textblock}}
|
|
2762
|
844 |
|
|
2764
|
845 |
\end{frame}}
|
|
|
846 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
847 |
*}
|
|
|
848 |
|
|
|
849 |
|
|
|
850 |
text_raw {*
|
|
|
851 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
852 |
\mode<presentation>{
|
|
|
853 |
\begin{frame}[c]
|
|
|
854 |
\frametitle{No Automata?}
|
|
|
855 |
|
|
|
856 |
You might be wondering why I did not use any automata:
|
|
|
857 |
|
|
|
858 |
\begin{itemize}
|
|
|
859 |
\item A \alert{regular language} is one where there is a DFA that
|
|
|
860 |
recognises it.\bigskip\pause
|
|
|
861 |
\end{itemize}
|
|
|
862 |
|
|
|
863 |
|
|
|
864 |
I can think of two reasons why this is a good definition:\medskip
|
|
|
865 |
\begin{itemize}
|
|
|
866 |
\item pumping lemma
|
|
|
867 |
\item closure properties of regular languages (closed under complement)
|
|
|
868 |
\end{itemize}
|
|
|
869 |
|
|
|
870 |
\end{frame}}
|
|
|
871 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
872 |
|
|
|
873 |
*}
|
|
|
874 |
|
|
|
875 |
text_raw {*
|
|
|
876 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
877 |
\mode<presentation>{
|
|
|
878 |
\begin{frame}[t]
|
|
|
879 |
\frametitle{Really Bad News!}
|
|
|
880 |
|
|
|
881 |
DFAs are bad news for formalisations in theorem provers. They might
|
|
|
882 |
be represented as:
|
|
|
883 |
|
|
2762
|
884 |
\begin{itemize}
|
|
2764
|
885 |
\item graphs
|
|
|
886 |
\item matrices
|
|
|
887 |
\item partial functions
|
|
|
888 |
\end{itemize}
|
|
|
889 |
|
|
|
890 |
All constructions are messy to reason about.\bigskip\bigskip
|
|
|
891 |
\pause
|
|
|
892 |
|
|
|
893 |
\small
|
|
|
894 |
\only<2>{
|
|
|
895 |
Constable et al needed (on and off) 18 months for a 3-person team
|
|
|
896 |
to formalise automata theory in Nuprl including Myhill-Nerode. There is
|
|
|
897 |
only very little other formalised work on regular languages I know of
|
|
|
898 |
in Coq, Isabelle and HOL.}
|
|
|
899 |
\only<3>{typical textbook reasoning goes like: ``\ldots if \smath{M} and \smath{N} are any two
|
|
|
900 |
automata with no inaccessible states \ldots''
|
|
|
901 |
}
|
|
|
902 |
|
|
|
903 |
\end{frame}}
|
|
|
904 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
905 |
|
|
|
906 |
*}
|
|
|
907 |
|
|
|
908 |
text_raw {*
|
|
|
909 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
910 |
\mode<presentation>{
|
|
|
911 |
\begin{frame}[c]
|
|
|
912 |
\frametitle{\LARGE The Myhill-Nerode Theorem}
|
|
|
913 |
|
|
|
914 |
\begin{itemize}
|
|
|
915 |
\item provides necessary and suf\!ficient conditions for a language
|
|
|
916 |
being regular (pumping lemma only necessary)\medskip
|
|
|
917 |
|
|
|
918 |
\item will help with closure properties of regular languages\bigskip\pause
|
|
|
919 |
|
|
|
920 |
\item key is the equivalence relation:\smallskip
|
|
|
921 |
\begin{center}
|
|
|
922 |
\smath{x \approx_{L} y \,\dn\, \forall z.\; x @ z \in L \Leftrightarrow y @ z \in L}
|
|
|
923 |
\end{center}
|
|
|
924 |
\end{itemize}
|
|
|
925 |
|
|
|
926 |
\end{frame}}
|
|
|
927 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
928 |
|
|
|
929 |
*}
|
|
2762
|
930 |
|
|
2764
|
931 |
text_raw {*
|
|
|
932 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
933 |
\mode<presentation>{
|
|
|
934 |
\begin{frame}[c]
|
|
|
935 |
\frametitle{\LARGE The Myhill-Nerode Theorem}
|
|
|
936 |
|
|
|
937 |
\mbox{}\\[5cm]
|
|
|
938 |
|
|
|
939 |
\begin{itemize}
|
|
|
940 |
\item \smath{\text{finite}\, (U\!N\!IV /\!/ \approx_L) \;\Leftrightarrow\; L\; \text{is regular}}
|
|
|
941 |
\end{itemize}
|
|
|
942 |
|
|
|
943 |
\end{frame}}
|
|
|
944 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
945 |
|
|
|
946 |
*}
|
|
|
947 |
|
|
|
948 |
text_raw {*
|
|
|
949 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
950 |
\mode<presentation>{
|
|
|
951 |
\begin{frame}[c]
|
|
|
952 |
\frametitle{\LARGE Equivalence Classes}
|
|
|
953 |
|
|
|
954 |
\begin{itemize}
|
|
|
955 |
\item \smath{L = []}
|
|
|
956 |
\begin{center}
|
|
|
957 |
\smath{\Big\{\{[]\},\; U\!N\!IV - \{[]\}\Big\}}
|
|
|
958 |
\end{center}\bigskip\bigskip
|
|
|
959 |
|
|
|
960 |
\item \smath{L = [c]}
|
|
|
961 |
\begin{center}
|
|
|
962 |
\smath{\Big\{\{[]\},\; \{[c]\},\; U\!N\!IV - \{[], [c]\}\Big\}}
|
|
|
963 |
\end{center}\bigskip\bigskip
|
|
|
964 |
|
|
|
965 |
\item \smath{L = \varnothing}
|
|
|
966 |
\begin{center}
|
|
|
967 |
\smath{\Big\{U\!N\!IV\Big\}}
|
|
|
968 |
\end{center}
|
|
|
969 |
|
|
|
970 |
\end{itemize}
|
|
|
971 |
|
|
|
972 |
\end{frame}}
|
|
|
973 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
974 |
|
|
|
975 |
*}
|
|
|
976 |
|
|
|
977 |
text_raw {*
|
|
|
978 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
979 |
\mode<presentation>{
|
|
|
980 |
\begin{frame}[c]
|
|
|
981 |
\frametitle{\LARGE Regular Languages}
|
|
|
982 |
|
|
|
983 |
\begin{itemize}
|
|
|
984 |
\item \smath{L} is regular \smath{\dn} if there is an automaton \smath{M}
|
|
|
985 |
such that \smath{\mathbb{L}(M) = L}\\[1.5cm]
|
|
2762
|
986 |
|
|
2764
|
987 |
\item Myhill-Nerode:
|
|
2762
|
988 |
|
|
|
989 |
\begin{center}
|
|
2764
|
990 |
\begin{tabular}{l}
|
|
|
991 |
finite $\Rightarrow$ regular\\
|
|
|
992 |
\;\;\;\smath{\text{finite}\,(U\!N\!IV /\!/ \approx_L) \Rightarrow \exists r. L = \mathbb{L}(r)}\\[3mm]
|
|
|
993 |
regular $\Rightarrow$ finite\\
|
|
|
994 |
\;\;\;\smath{\text{finite}\, (U\!N\!IV /\!/ \approx_{\mathbb{L}(r)})}
|
|
|
995 |
\end{tabular}
|
|
|
996 |
\end{center}
|
|
|
997 |
|
|
|
998 |
\end{itemize}
|
|
|
999 |
|
|
|
1000 |
\end{frame}}
|
|
|
1001 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1002 |
|
|
|
1003 |
*}
|
|
|
1004 |
|
|
|
1005 |
text_raw {*
|
|
|
1006 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1007 |
\mode<presentation>{
|
|
|
1008 |
\begin{frame}[c]
|
|
|
1009 |
\frametitle{\LARGE Final States}
|
|
|
1010 |
|
|
|
1011 |
\mbox{}\\[3cm]
|
|
|
1012 |
|
|
|
1013 |
\begin{itemize}
|
|
|
1014 |
\item \smath{\text{final}_L\,X \dn}\\
|
|
|
1015 |
\smath{\hspace{6mm}X \in (U\!N\!IV /\!/\approx_L) \;\wedge\; \forall s \in X.\; s \in L}
|
|
|
1016 |
\smallskip
|
|
|
1017 |
\item we can prove: \smath{L = \bigcup \{X.\;\text{final}_L\,X\}}
|
|
|
1018 |
|
|
|
1019 |
\end{itemize}
|
|
|
1020 |
|
|
|
1021 |
\end{frame}}
|
|
|
1022 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1023 |
*}
|
|
|
1024 |
|
|
|
1025 |
text_raw {*
|
|
|
1026 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1027 |
\mode<presentation>{
|
|
|
1028 |
\begin{frame}[c]
|
|
|
1029 |
\frametitle{\LARGE Transitions between\\[-3mm] Equivalence Classes}
|
|
|
1030 |
|
|
|
1031 |
\smath{L = \{[c]\}}
|
|
|
1032 |
|
|
|
1033 |
\begin{tabular}{@ {\hspace{-7mm}}cc}
|
|
|
1034 |
\begin{tabular}{c}
|
|
|
1035 |
\begin{tikzpicture}[shorten >=1pt,node distance=2cm,auto, ultra thick]
|
|
|
1036 |
\tikzstyle{state}=[circle,thick,draw=blue!75,fill=blue!20,minimum size=0mm]
|
|
|
1037 |
|
|
|
1038 |
%\draw[help lines] (0,0) grid (3,2);
|
|
|
1039 |
|
|
|
1040 |
\node[state,initial] (q_0) {$R_1$};
|
|
|
1041 |
\node[state,accepting] (q_1) [above right of=q_0] {$R_2$};
|
|
|
1042 |
\node[state] (q_2) [below right of=q_0] {$R_3$};
|
|
|
1043 |
|
|
|
1044 |
\path[->] (q_0) edge node {c} (q_1)
|
|
|
1045 |
edge node [swap] {$\Sigma-{c}$} (q_2)
|
|
|
1046 |
(q_2) edge [loop below] node {$\Sigma$} ()
|
|
|
1047 |
(q_1) edge node {$\Sigma$} (q_2);
|
|
|
1048 |
\end{tikzpicture}
|
|
|
1049 |
\end{tabular}
|
|
|
1050 |
&
|
|
|
1051 |
\begin{tabular}[t]{ll}
|
|
|
1052 |
\\[-20mm]
|
|
|
1053 |
\multicolumn{2}{l}{\smath{U\!N\!IV /\!/\approx_L} produces}\\[4mm]
|
|
|
1054 |
|
|
|
1055 |
\smath{R_1}: & \smath{\{[]\}}\\
|
|
|
1056 |
\smath{R_2}: & \smath{\{[c]\}}\\
|
|
|
1057 |
\smath{R_3}: & \smath{U\!N\!IV - \{[], [c]\}}\\[6mm]
|
|
|
1058 |
\multicolumn{2}{l}{\onslide<2->{\smath{X \stackrel{c}{\longrightarrow} Y \dn X ; [c] \subseteq Y}}}
|
|
|
1059 |
\end{tabular}
|
|
|
1060 |
|
|
|
1061 |
\end{tabular}
|
|
|
1062 |
|
|
|
1063 |
\end{frame}}
|
|
|
1064 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1065 |
*}
|
|
|
1066 |
|
|
|
1067 |
|
|
|
1068 |
text_raw {*
|
|
|
1069 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1070 |
\mode<presentation>{
|
|
|
1071 |
\begin{frame}[c]
|
|
|
1072 |
\frametitle{\LARGE Systems of Equations}
|
|
|
1073 |
|
|
|
1074 |
Inspired by a method of Brzozowski\;'64, we can build an equational system
|
|
|
1075 |
characterising the equivalence classes:
|
|
|
1076 |
|
|
|
1077 |
\begin{center}
|
|
|
1078 |
\begin{tabular}{@ {\hspace{-20mm}}c}
|
|
|
1079 |
\\[-13mm]
|
|
|
1080 |
\begin{tikzpicture}[shorten >=1pt,node distance=2cm,auto, ultra thick]
|
|
|
1081 |
\tikzstyle{state}=[circle,thick,draw=blue!75,fill=blue!20,minimum size=0mm]
|
|
|
1082 |
|
|
|
1083 |
%\draw[help lines] (0,0) grid (3,2);
|
|
|
1084 |
|
|
|
1085 |
\node[state,initial] (p_0) {$R_1$};
|
|
|
1086 |
\node[state,accepting] (p_1) [right of=q_0] {$R_2$};
|
|
|
1087 |
|
|
|
1088 |
\path[->] (p_0) edge [bend left] node {a} (p_1)
|
|
|
1089 |
edge [loop above] node {b} ()
|
|
|
1090 |
(p_1) edge [loop above] node {a} ()
|
|
|
1091 |
edge [bend left] node {b} (p_0);
|
|
|
1092 |
\end{tikzpicture}\\
|
|
|
1093 |
\\[-13mm]
|
|
|
1094 |
\end{tabular}
|
|
|
1095 |
\end{center}
|
|
|
1096 |
|
|
|
1097 |
\begin{center}
|
|
|
1098 |
\begin{tabular}{@ {\hspace{-6mm}}ll@ {\hspace{1mm}}c@ {\hspace{1mm}}l}
|
|
|
1099 |
& \smath{R_1} & \smath{\equiv} & \smath{R_1;b + R_2;b \onslide<2->{\alert<2>{+ \lambda;[]}}}\\
|
|
|
1100 |
& \smath{R_2} & \smath{\equiv} & \smath{R_1;a + R_2;a}\medskip\\
|
|
|
1101 |
\onslide<3->{we can prove}
|
|
|
1102 |
& \onslide<3->{\smath{R_1}} & \onslide<3->{\smath{=}}
|
|
|
1103 |
& \onslide<3->{\smath{R_1; \mathbb{L}(b) \,\cup\, R_2;\mathbb{L}(b) \,\cup\, \{[]\};\{[]\}}}\\
|
|
|
1104 |
& \onslide<3->{\smath{R_2}} & \onslide<3->{\smath{=}}
|
|
|
1105 |
& \onslide<3->{\smath{R_1; \mathbb{L}(a) \,\cup\, R_2;\mathbb{L}(a)}}\\
|
|
|
1106 |
\end{tabular}
|
|
|
1107 |
\end{center}
|
|
|
1108 |
|
|
|
1109 |
\end{frame}}
|
|
|
1110 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1111 |
*}
|
|
|
1112 |
|
|
|
1113 |
|
|
|
1114 |
text_raw {*
|
|
|
1115 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1116 |
\mode<presentation>{
|
|
|
1117 |
\begin{frame}<1>[t]
|
|
2762
|
1118 |
\small
|
|
2764
|
1119 |
|
|
|
1120 |
\begin{center}
|
|
|
1121 |
\begin{tabular}{l@ {\hspace{1mm}}c@ {\hspace{1mm}}ll}
|
|
|
1122 |
\onslide<1->{\smath{R_1}} & \onslide<1->{\smath{=}}
|
|
|
1123 |
& \onslide<1->{\smath{R_1; b + R_2; b + \lambda;[]}}\\
|
|
|
1124 |
\onslide<1->{\smath{R_2}} & \onslide<1->{\smath{=}}
|
|
|
1125 |
& \onslide<1->{\smath{R_1; a + R_2; a}}\\
|
|
|
1126 |
|
|
|
1127 |
& & & \onslide<2->{by Arden}\\
|
|
|
1128 |
|
|
|
1129 |
\onslide<2->{\smath{R_1}} & \onslide<2->{\smath{=}}
|
|
|
1130 |
& \onslide<2->{\smath{R_1; b + R_2; b + \lambda;[]}}\\
|
|
|
1131 |
\onslide<2->{\smath{R_2}} & \onslide<2->{\smath{=}}
|
|
|
1132 |
& \only<2>{\smath{R_1; a + R_2; a}}%
|
|
|
1133 |
\only<3->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1134 |
|
|
|
1135 |
& & & \onslide<4->{by Arden}\\
|
|
|
1136 |
|
|
|
1137 |
\onslide<4->{\smath{R_1}} & \onslide<4->{\smath{=}}
|
|
|
1138 |
& \onslide<4->{\smath{R_2; b \cdot b^\star+ \lambda;b^\star}}\\
|
|
|
1139 |
\onslide<4->{\smath{R_2}} & \onslide<4->{\smath{=}}
|
|
|
1140 |
& \onslide<4->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1141 |
|
|
|
1142 |
& & & \onslide<5->{by substitution}\\
|
|
|
1143 |
|
|
|
1144 |
\onslide<5->{\smath{R_1}} & \onslide<5->{\smath{=}}
|
|
|
1145 |
& \onslide<5->{\smath{R_1; a\cdot a^\star \cdot b \cdot b^\star+ \lambda;b^\star}}\\
|
|
|
1146 |
\onslide<5->{\smath{R_2}} & \onslide<5->{\smath{=}}
|
|
|
1147 |
& \onslide<5->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1148 |
|
|
|
1149 |
& & & \onslide<6->{by Arden}\\
|
|
|
1150 |
|
|
|
1151 |
\onslide<6->{\smath{R_1}} & \onslide<6->{\smath{=}}
|
|
|
1152 |
& \onslide<6->{\smath{\lambda;b^\star\cdot (a\cdot a^\star \cdot b \cdot b^\star)^\star}}\\
|
|
|
1153 |
\onslide<6->{\smath{R_2}} & \onslide<6->{\smath{=}}
|
|
|
1154 |
& \onslide<6->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1155 |
|
|
|
1156 |
& & & \onslide<7->{by substitution}\\
|
|
|
1157 |
|
|
|
1158 |
\onslide<7->{\smath{R_1}} & \onslide<7->{\smath{=}}
|
|
|
1159 |
& \onslide<7->{\smath{\lambda;b^\star\cdot (a\cdot a^\star \cdot b \cdot b^\star)^\star}}\\
|
|
|
1160 |
\onslide<7->{\smath{R_2}} & \onslide<7->{\smath{=}}
|
|
|
1161 |
& \onslide<7->{\smath{\lambda; b^\star\cdot (a\cdot a^\star \cdot b \cdot b^\star)^\star
|
|
|
1162 |
\cdot a\cdot a^\star}}\\
|
|
|
1163 |
\end{tabular}
|
|
2762
|
1164 |
\end{center}
|
|
|
1165 |
|
|
|
1166 |
\end{frame}}
|
|
|
1167 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1168 |
*}
|
|
|
1169 |
|
|
|
1170 |
text_raw {*
|
|
|
1171 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1172 |
\mode<presentation>{
|
|
2764
|
1173 |
\begin{frame}[c]
|
|
|
1174 |
\frametitle{\LARGE A Variant of Arden's Lemma}
|
|
|
1175 |
|
|
|
1176 |
{\bf Arden's Lemma:}\smallskip
|
|
|
1177 |
|
|
|
1178 |
If \smath{[] \not\in A} then
|
|
|
1179 |
\begin{center}
|
|
|
1180 |
\smath{X = X; A + \text{something}}
|
|
|
1181 |
\end{center}
|
|
|
1182 |
has the (unique) solution
|
|
|
1183 |
\begin{center}
|
|
|
1184 |
\smath{X = \text{something} ; A^\star}
|
|
|
1185 |
\end{center}
|
|
|
1186 |
|
|
|
1187 |
|
|
|
1188 |
\end{frame}}
|
|
|
1189 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1190 |
*}
|
|
|
1191 |
|
|
|
1192 |
|
|
|
1193 |
text_raw {*
|
|
|
1194 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1195 |
\mode<presentation>{
|
|
|
1196 |
\begin{frame}<1->[t]
|
|
|
1197 |
\small
|
|
|
1198 |
|
|
|
1199 |
\begin{center}
|
|
|
1200 |
\begin{tabular}{l@ {\hspace{1mm}}c@ {\hspace{1mm}}ll}
|
|
|
1201 |
\onslide<1->{\smath{R_1}} & \onslide<1->{\smath{=}}
|
|
|
1202 |
& \onslide<1->{\smath{R_1; b + R_2; b + \lambda;[]}}\\
|
|
|
1203 |
\onslide<1->{\smath{R_2}} & \onslide<1->{\smath{=}}
|
|
|
1204 |
& \onslide<1->{\smath{R_1; a + R_2; a}}\\
|
|
|
1205 |
|
|
|
1206 |
& & & \onslide<2->{by Arden}\\
|
|
|
1207 |
|
|
|
1208 |
\onslide<2->{\smath{R_1}} & \onslide<2->{\smath{=}}
|
|
|
1209 |
& \onslide<2->{\smath{R_1; b + R_2; b + \lambda;[]}}\\
|
|
|
1210 |
\onslide<2->{\smath{R_2}} & \onslide<2->{\smath{=}}
|
|
|
1211 |
& \only<2>{\smath{R_1; a + R_2; a}}%
|
|
|
1212 |
\only<3->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1213 |
|
|
|
1214 |
& & & \onslide<4->{by Arden}\\
|
|
|
1215 |
|
|
|
1216 |
\onslide<4->{\smath{R_1}} & \onslide<4->{\smath{=}}
|
|
|
1217 |
& \onslide<4->{\smath{R_2; b \cdot b^\star+ \lambda;b^\star}}\\
|
|
|
1218 |
\onslide<4->{\smath{R_2}} & \onslide<4->{\smath{=}}
|
|
|
1219 |
& \onslide<4->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1220 |
|
|
|
1221 |
& & & \onslide<5->{by substitution}\\
|
|
|
1222 |
|
|
|
1223 |
\onslide<5->{\smath{R_1}} & \onslide<5->{\smath{=}}
|
|
|
1224 |
& \onslide<5->{\smath{R_1; a\cdot a^\star \cdot b \cdot b^\star+ \lambda;b^\star}}\\
|
|
|
1225 |
\onslide<5->{\smath{R_2}} & \onslide<5->{\smath{=}}
|
|
|
1226 |
& \onslide<5->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1227 |
|
|
|
1228 |
& & & \onslide<6->{by Arden}\\
|
|
|
1229 |
|
|
|
1230 |
\onslide<6->{\smath{R_1}} & \onslide<6->{\smath{=}}
|
|
|
1231 |
& \onslide<6->{\smath{\lambda;b^\star\cdot (a\cdot a^\star \cdot b \cdot b^\star)^\star}}\\
|
|
|
1232 |
\onslide<6->{\smath{R_2}} & \onslide<6->{\smath{=}}
|
|
|
1233 |
& \onslide<6->{\smath{R_1; a\cdot a^\star}}\\
|
|
|
1234 |
|
|
|
1235 |
& & & \onslide<7->{by substitution}\\
|
|
|
1236 |
|
|
|
1237 |
\onslide<7->{\smath{R_1}} & \onslide<7->{\smath{=}}
|
|
|
1238 |
& \onslide<7->{\smath{\lambda;b^\star\cdot (a\cdot a^\star \cdot b \cdot b^\star)^\star}}\\
|
|
|
1239 |
\onslide<7->{\smath{R_2}} & \onslide<7->{\smath{=}}
|
|
|
1240 |
& \onslide<7->{\smath{\lambda; b^\star\cdot (a\cdot a^\star \cdot b \cdot b^\star)^\star
|
|
|
1241 |
\cdot a\cdot a^\star}}\\
|
|
|
1242 |
\end{tabular}
|
|
|
1243 |
\end{center}
|
|
|
1244 |
|
|
|
1245 |
\only<8->{
|
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|
1246 |
\begin{textblock}{6}(2.5,4)
|
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|
1247 |
\begin{block}{}
|
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|
1248 |
\begin{minipage}{8cm}\raggedright
|
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2762
|
1249 |
|
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2764
|
1250 |
\begin{tikzpicture}[shorten >=1pt,node distance=2cm,auto, ultra thick, inner sep=1mm]
|
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|
1251 |
\tikzstyle{state}=[circle,thick,draw=blue!75,fill=blue!20,minimum size=0mm]
|
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1252 |
|
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|
1253 |
%\draw[help lines] (0,0) grid (3,2);
|
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|
1254 |
|
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|
1255 |
\node[state,initial] (p_0) {$R_1$};
|
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|
1256 |
\node[state,accepting] (p_1) [right of=q_0] {$R_2$};
|
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|
1257 |
|
|
|
1258 |
\path[->] (p_0) edge [bend left] node {a} (p_1)
|
|
|
1259 |
edge [loop above] node {b} ()
|
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|
1260 |
(p_1) edge [loop above] node {a} ()
|
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|
1261 |
edge [bend left] node {b} (p_0);
|
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|
1262 |
\end{tikzpicture}
|
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|
1263 |
|
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|
1264 |
\end{minipage}
|
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|
1265 |
\end{block}
|
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|
1266 |
\end{textblock}}
|
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|
1267 |
|
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|
1268 |
\end{frame}}
|
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|
1269 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1270 |
*}
|
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|
1271 |
|
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|
1272 |
|
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|
1273 |
text_raw {*
|
|
|
1274 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1275 |
\mode<presentation>{
|
|
|
1276 |
\begin{frame}[c]
|
|
|
1277 |
\frametitle{\LARGE The Equ's Solving Algorithm}
|
|
|
1278 |
|
|
2762
|
1279 |
\begin{itemize}
|
|
2764
|
1280 |
\item The algorithm must terminate: Arden makes one equation smaller;
|
|
|
1281 |
substitution deletes one variable from the right-hand sides.\bigskip
|
|
|
1282 |
|
|
|
1283 |
\item We need to maintain the invariant that Arden is applicable
|
|
|
1284 |
(if \smath{[] \not\in A} then \ldots):\medskip
|
|
|
1285 |
|
|
|
1286 |
\begin{center}\small
|
|
|
1287 |
\begin{tabular}{l@ {\hspace{1mm}}c@ {\hspace{1mm}}ll}
|
|
|
1288 |
\smath{R_1} & \smath{=} & \smath{R_1; b + R_2; b + \lambda;[]}\\
|
|
|
1289 |
\smath{R_2} & \smath{=} & \smath{R_1; a + R_2; a}\\
|
|
|
1290 |
|
|
|
1291 |
& & & by Arden\\
|
|
|
1292 |
|
|
|
1293 |
\smath{R_1} & \smath{=} & \smath{R_1; b + R_2; b + \lambda;[]}\\
|
|
|
1294 |
\smath{R_2} & \smath{=} & \smath{R_1; a\cdot a^\star}\\
|
|
|
1295 |
\end{tabular}
|
|
|
1296 |
\end{center}
|
|
|
1297 |
|
|
|
1298 |
\end{itemize}
|
|
|
1299 |
|
|
|
1300 |
|
|
|
1301 |
\end{frame}}
|
|
|
1302 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1303 |
*}
|
|
|
1304 |
|
|
|
1305 |
|
|
|
1306 |
text_raw {*
|
|
|
1307 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1308 |
\mode<presentation>{
|
|
|
1309 |
\begin{frame}[c]
|
|
|
1310 |
\frametitle{\LARGE Other Direction}
|
|
|
1311 |
|
|
|
1312 |
One has to prove
|
|
|
1313 |
|
|
|
1314 |
\begin{center}
|
|
|
1315 |
\smath{\text{finite} (U\!N\!IV /\!/ \approx_{\mathbb{L}(r)})}
|
|
|
1316 |
\end{center}
|
|
|
1317 |
|
|
|
1318 |
by induction on \smath{r}. Not trivial, but after a bit
|
|
|
1319 |
of thinking, one can prove that if
|
|
|
1320 |
|
|
|
1321 |
\begin{center}
|
|
|
1322 |
\smath{\text{finite} (U\!N\!IV /\!/ \approx_{\mathbb{L}(r_1)})}\hspace{5mm}
|
|
|
1323 |
\smath{\text{finite} (U\!N\!IV /\!/ \approx_{\mathbb{L}(r_2)})}
|
|
|
1324 |
\end{center}
|
|
|
1325 |
|
|
|
1326 |
then
|
|
2762
|
1327 |
|
|
2764
|
1328 |
\begin{center}
|
|
|
1329 |
\smath{\text{finite} (U\!N\!IV /\!/ \approx_{\mathbb{L}(r_1) \,\cup\, \mathbb{L}(r_2)})}
|
|
|
1330 |
\end{center}
|
|
|
1331 |
|
|
|
1332 |
|
|
|
1333 |
|
|
|
1334 |
\end{frame}}
|
|
|
1335 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1336 |
*}
|
|
|
1337 |
|
|
|
1338 |
|
|
|
1339 |
text_raw {*
|
|
|
1340 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1341 |
\mode<presentation>{
|
|
|
1342 |
\begin{frame}[c]
|
|
|
1343 |
\frametitle{\LARGE What Have We Achieved?}
|
|
|
1344 |
|
|
|
1345 |
\begin{itemize}
|
|
|
1346 |
\item \smath{\text{finite}\, (U\!N\!IV /\!/ \approx_L) \;\Leftrightarrow\; L\; \text{is regular}}
|
|
|
1347 |
\bigskip\pause
|
|
|
1348 |
\item regular languages are closed under complementation; this is easy
|
|
|
1349 |
\begin{center}
|
|
|
1350 |
\smath{U\!N\!IV /\!/ \approx_L \;\;=\;\; U\!N\!IV /\!/ \approx_{-L}}
|
|
|
1351 |
\end{center}
|
|
|
1352 |
\end{itemize}
|
|
2762
|
1353 |
|
|
2764
|
1354 |
|
|
|
1355 |
\end{frame}}
|
|
|
1356 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1357 |
*}
|
|
|
1358 |
|
|
|
1359 |
text_raw {*
|
|
|
1360 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1361 |
\mode<presentation>{
|
|
|
1362 |
\begin{frame}[c]
|
|
|
1363 |
\frametitle{\LARGE Examples}
|
|
|
1364 |
|
|
|
1365 |
\begin{itemize}
|
|
|
1366 |
\item \smath{L \equiv \Sigma^\star 0 \Sigma} is regular
|
|
|
1367 |
\begin{quote}\small
|
|
|
1368 |
\begin{tabular}{lcl}
|
|
|
1369 |
\smath{A_1} & \smath{=} & \smath{\Sigma^\star 00}\\
|
|
|
1370 |
\smath{A_2} & \smath{=} & \smath{\Sigma^\star 01}\\
|
|
|
1371 |
\smath{A_3} & \smath{=} & \smath{\Sigma^\star 10 \cup \{0\}}\\
|
|
|
1372 |
\smath{A_4} & \smath{=} & \smath{\Sigma^\star 11 \cup \{1\} \cup \{[]\}}\\
|
|
|
1373 |
\end{tabular}
|
|
|
1374 |
\end{quote}
|
|
|
1375 |
|
|
|
1376 |
\item \smath{L \equiv \{ 0^n 1^n \,|\, n \ge 0\}} is not regular
|
|
|
1377 |
\begin{quote}\small
|
|
|
1378 |
\begin{tabular}{lcl}
|
|
|
1379 |
\smath{B_0} & \smath{=} & \smath{\{0^n 1^n \,|\, n \ge 0\}}\\
|
|
|
1380 |
\smath{B_1} & \smath{=} & \smath{\{0^n 1^{(n-1)} \,|\, n \ge 1\}}\\
|
|
|
1381 |
\smath{B_2} & \smath{=} & \smath{\{0^n 1^{(n-2)} \,|\, n \ge 2\}}\\
|
|
|
1382 |
\smath{B_3} & \smath{=} & \smath{\{0^n 1^{(n-3)} \,|\, n \ge 3\}}\\
|
|
|
1383 |
& \smath{\vdots} &\\
|
|
|
1384 |
\end{tabular}
|
|
|
1385 |
\end{quote}
|
|
2762
|
1386 |
\end{itemize}
|
|
|
1387 |
|
|
|
1388 |
\end{frame}}
|
|
|
1389 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1390 |
*}
|
|
|
1391 |
|
|
|
1392 |
|
|
|
1393 |
text_raw {*
|
|
|
1394 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1395 |
\mode<presentation>{
|
|
2764
|
1396 |
\begin{frame}[c]
|
|
|
1397 |
\frametitle{\LARGE What We Have Not Achieved}
|
|
|
1398 |
|
|
|
1399 |
\begin{itemize}
|
|
|
1400 |
\item regular expressions are not good if you look for a minimal
|
|
|
1401 |
one for a language (DFAs have this notion)\pause\bigskip
|
|
|
1402 |
|
|
|
1403 |
\item Is there anything to be said about context free languages:\medskip
|
|
|
1404 |
|
|
|
1405 |
\begin{quote}
|
|
|
1406 |
A context free language is where every string can be recognised by
|
|
|
1407 |
a pushdown automaton.\bigskip
|
|
|
1408 |
\end{quote}
|
|
|
1409 |
\end{itemize}
|
|
|
1410 |
|
|
|
1411 |
\textcolor{gray}{\footnotesize Yes. Derivatives also work for c-f grammars. Ongoing work.}
|
|
|
1412 |
|
|
|
1413 |
\end{frame}}
|
|
|
1414 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1415 |
*}
|
|
|
1416 |
|
|
|
1417 |
|
|
|
1418 |
text_raw {*
|
|
|
1419 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1420 |
\mode<presentation>{
|
|
|
1421 |
\begin{frame}[c]
|
|
|
1422 |
\frametitle{\LARGE Conclusion}
|
|
|
1423 |
|
|
|
1424 |
\begin{itemize}
|
|
|
1425 |
\item We formalised the Myhill-Nerode theorem based on
|
|
|
1426 |
regular expressions (DFA are difficult to deal with in a theorem prover).\smallskip
|
|
|
1427 |
|
|
|
1428 |
\item Seems to be a common theme: algorithms need to be reformulated
|
|
|
1429 |
to better suit formal treatment.\smallskip
|
|
|
1430 |
|
|
|
1431 |
\item The most interesting aspect is that we are able to
|
|
|
1432 |
implement the matcher directly inside the theorem prover
|
|
|
1433 |
(ongoing work).\smallskip
|
|
|
1434 |
|
|
|
1435 |
\item Parsing is a vast field and seems to offer new results.
|
|
|
1436 |
\end{itemize}
|
|
|
1437 |
|
|
|
1438 |
\end{frame}}
|
|
|
1439 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1440 |
*}
|
|
|
1441 |
|
|
|
1442 |
text_raw {*
|
|
|
1443 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
|
1444 |
\mode<presentation>{
|
|
|
1445 |
\begin{frame}<1>[b]
|
|
2762
|
1446 |
\frametitle{
|
|
|
1447 |
\begin{tabular}{c}
|
|
2764
|
1448 |
\mbox{}\\[13mm]
|
|
2762
|
1449 |
\alert{\LARGE Thank you very much!}\\
|
|
|
1450 |
\alert{\Large Questions?}
|
|
|
1451 |
\end{tabular}}
|
|
2764
|
1452 |
|
|
|
1453 |
%\begin{center}
|
|
|
1454 |
%\bf \underline{Short Bio:}
|
|
|
1455 |
%\end{center}
|
|
|
1456 |
%\mbox{}\\[-17mm]\mbox{}\small
|
|
|
1457 |
%\begin{itemize}
|
|
|
1458 |
%\item PhD in Cambridge
|
|
|
1459 |
%\item Emmy-Noether Fellowship in Munich
|
|
|
1460 |
%\item main results in nominal reasoning and nominal unification
|
|
|
1461 |
%\end{itemize}
|
|
|
1462 |
|
|
2762
|
1463 |
\end{frame}}
|
|
2764
|
1464 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
|
2762
|
1465 |
*}
|
|
|
1466 |
|
|
|
1467 |
|
|
|
1468 |
|
|
2764
|
1469 |
|
|
2762
|
1470 |
(*<*)
|
|
|
1471 |
end
|
|
|
1472 |
(*>*) |