\documentclass{article}\usepackage{charter}\usepackage{hyperref}\usepackage{amssymb}\usepackage{proof}\begin{document}\section*{Homework 7}\begin{enumerate}\item Suppose a judgement is of the form:\begin{center}$Alice\;\textit{says}\;S \wedge Bob\;\textit{says}\;S \vdash Bob\;\textit{says}\;S \wedge Alice\;\textit{says}\;S$\end{center}Assume you want to use the inference rule\begin{center}\mbox{\infer{\Gamma \vdash F_1 \wedge F_2}{\Gamma \vdash F_1 & \Gamma \vdash F_2}}\end{center}for constructing a proof of the judgement. What do the premises look like? \item The informal meaning of the formula \mbox{$P\;\mapsto\;Q$} is `$P$ speaks for$Q$'. Give a definition for this formula in terms of $\textit{says}$.\item In Unix, what should be the general architecture of a network application that processes potentially hostile data from the Internet? (Hint: Focus on the fact that in Unixyou can give different privileges to processes.)\item Explain what are the differences between dictionary and brute forcing attacks against passwords.\end{enumerate}\end{document}%%% Local Variables: %%% mode: latex%%% TeX-master: t%%% End: