# HG changeset patch # User Christian Urban # Date 1349226895 -3600 # Node ID 4d81b2dc827188ae4221e93a20c886fa76600bbe # Parent 32d56fef14a7a45a01de7f7feed999b6255a0ac9 tuned diff -r 32d56fef14a7 -r 4d81b2dc8271 slides02.pdf Binary file slides02.pdf has changed diff -r 32d56fef14a7 -r 4d81b2dc8271 slides02.tex --- a/slides02.tex Wed Oct 03 01:41:08 2012 +0100 +++ b/slides02.tex Wed Oct 03 02:14:55 2012 +0100 @@ -360,6 +360,109 @@ \end{frame}} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[t] +\frametitle{\begin{tabular}{c}Proofs about Rexp\end{tabular}} + +Remember their inductive definition:\\[5cm] + +\begin{textblock}{6}(5,5) + \begin{tabular}{@ {}rrl} + \bl{r} & \bl{$::=$} & \bl{$\varnothing$}\\ + & \bl{$\mid$} & \bl{$\epsilon$} \\ + & \bl{$\mid$} & \bl{c} \\ + & \bl{$\mid$} & \bl{r$_1$ $\cdot$ r$_2$}\\ + & \bl{$\mid$} & \bl{r$_1$ + r$_2$} \\ + & \bl{$\mid$} & \bl{r$^*$} \\ + \end{tabular} + \end{textblock} + +If we want to prove something, say a property \bl{$P$(r)}, for all regular expressions \bl{r} then \ldots + +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[c] +\frametitle{\begin{tabular}{c}Proofs about Rexp (2)\end{tabular}} + +\begin{itemize} +\item \bl{$P$} holds for \bl{$\varnothing$}, \bl{$\epsilon$} and \bl{c}\bigskip +\item \bl{$P$} holds for \bl{r$_1$ + r$_2$} under the assumption that \bl{$P$} already +holds for \bl{r$_1$} and \bl{r$_2$}.\bigskip +\item \bl{$P$} holds for \bl{r$_1$ $\cdot$ r$_2$} under the assumption that \bl{$P$} already +holds for \bl{r$_1$} and \bl{r$_2$}. +\item \bl{$P$} holds for \bl{r$^*$} under the assumption that \bl{$P$} already +holds for \bl{r}. +\end{itemize} + +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[c] +\frametitle{\begin{tabular}{c}Proofs about Rexp (3)\end{tabular}} + +Assume \bl{$P(r)$} is the property: + +\begin{center} +\bl{nullable(r)} if and only if \bl{"" $\in$ $L$(r)} +\end{center} + +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[c] +\frametitle{\begin{tabular}{c}Proofs about Strings\end{tabular}} + +If we want to prove something, say a property \bl{$P$(s)}, for all strings \bl{s} then \ldots\bigskip + +\begin{itemize} +\item \bl{$P$} holds for the empty string, and\medskip +\item \bl{$P$} holds for the string \bl{c::s} under the assumption that \bl{$P$} +already holds for \bl{s} +\end{itemize} +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[c] +\frametitle{\begin{tabular}{c}Regular Languages\end{tabular}} + +A language (set of strings) is \alert{regular} iff there exists +a regular expression that recognises all its strings. + +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[c] +\frametitle{\begin{tabular}{c}Automata\end{tabular}} + +A deterministic finite automaton consists of: + +\begin{itemize} +\item a set of states +\item one of these states is the start state +\item some states are accepting states, and +\item there is transition function\medskip + +\small +which takes a state as argument and a character and produces a new state\smallskip\\ +this function might not always be defined +\end{itemize} + +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + \end{document}