%% This is a LaTeX document. Hey, Emacs, -*- latex -*- , get it? \documentclass[12pt,a4paper]{article} \usepackage[francais]{babel} \usepackage[latin1]{inputenc} \usepackage{times} % A tribute to the worthy AMS: \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsthm} % \usepackage{mathrsfs} \usepackage{wasysym} \usepackage{url} % \theoremstyle{definition} \newtheorem{comcnt}{Tout}[subsection] \newcommand\thingy{% \refstepcounter{comcnt}\smallbreak\noindent\textbf{\thecomcnt.} } \newtheorem{defn}[comcnt]{Définition} \newtheorem{prop}[comcnt]{Proposition} \newtheorem{lem}[comcnt]{Lemme} \newtheorem{thm}[comcnt]{Théorème} \newtheorem{cor}[comcnt]{Corollaire} \newtheorem{rmk}[comcnt]{Remarque} \newtheorem{exmps}[comcnt]{Exemples} \newcommand{\limp}{\mathrel{\Rightarrow}} \newcommand{\liff}{\mathrel{\Longleftrightarrow}} \newcommand{\pgcd}{\operatorname{pgcd}} \newcommand{\ppcm}{\operatorname{ppcm}} \newcommand{\signe}{\operatorname{signe}} \newcommand{\tee}{\mathbin{\top}} \newcommand{\Frob}{\operatorname{Fr}} \renewcommand{\qedsymbol}{\smiley} % % % \begin{document} \pagestyle{empty} Exemple de $\mathbb{F}_8$ vu comme $\mathbb{F}_2[t]/(f)$ avec $f = t^3 + t + 1$ : Représentation par des polynômes de degré $<3$ en $t$ : {\footnotesize \begin{center} $ \begin{array}{r|cccccccc} +&\{0\}&\{1\}&\{2\}&\{3\}&\{4\}&\{5\}&\{6\}&\{7\}\\ \hline 0=\{0\}&\{0\}&\{1\}&\{2\}&\{3\}&\{4\}&\{5\}&\{6\}&\{7\}\\ 1=\{1\}&\{1\}&\{0\}&\{3\}&\{2\}&\{5\}&\{4\}&\{7\}&\{6\}\\ \bar t=\{2\}&\{2\}&\{3\}&\{0\}&\{1\}&\{6\}&\{7\}&\{4\}&\{5\}\\ \bar t+1=\{3\}&\{3\}&\{2\}&\{1\}&\{0\}&\{7\}&\{6\}&\{5\}&\{4\}\\ \bar t^2=\{4\}&\{4\}&\{5\}&\{6\}&\{7\}&\{0\}&\{1\}&\{2\}&\{3\}\\ \bar t^2+1=\{5\}&\{5\}&\{4\}&\{7\}&\{6\}&\{1\}&\{0\}&\{3\}&\{2\}\\ \bar t^2+\bar t=\{6\}&\{6\}&\{7\}&\{4\}&\{5\}&\{2\}&\{3\}&\{0\}&\{1\}\\ \bar t^2+\bar t+1=\{7\}&\{7\}&\{6\}&\{5\}&\{4\}&\{3\}&\{2\}&\{1\}&\{0\}\\ \end{array} $ \end{center} } {\footnotesize \begin{center} $ \begin{array}{r|cccccccc} \times&\{0\}&\{1\}&\{2\}&\{3\}&\{4\}&\{5\}&\{6\}&\{7\}\\ \hline 0=\{0\}&\{0\}&\{0\}&\{0\}&\{0\}&\{0\}&\{0\}&\{0\}&\{0\}\\ 1=\{1\}&\{0\}&\{1\}&\{2\}&\{3\}&\{4\}&\{5\}&\{6\}&\{7\}\\ \bar t=\{2\}&\{0\}&\{2\}&\{4\}&\{6\}&\{3\}&\{1\}&\{7\}&\{5\}\\ \bar t+1=\{3\}&\{0\}&\{3\}&\{6\}&\{5\}&\{7\}&\{4\}&\{1\}&\{2\}\\ \bar t^2=\{4\}&\{0\}&\{4\}&\{3\}&\{7\}&\{6\}&\{2\}&\{5\}&\{1\}\\ \bar t^2+1=\{5\}&\{0\}&\{5\}&\{1\}&\{4\}&\{2\}&\{7\}&\{3\}&\{6\}\\ \bar t^2+\bar t=\{6\}&\{0\}&\{6\}&\{7\}&\{1\}&\{5\}&\{3\}&\{2\}&\{4\}\\ \bar t^2+\bar t+1=\{7\}&\{0\}&\{7\}&\{5\}&\{2\}&\{1\}&\{6\}&\{4\}&\{3\}\\ \end{array} $ \end{center} } Représentation par des puissances de l'élément primitif $\bar t$ : {\footnotesize \begin{center} $ \begin{array}{r|cccccccc} +&[^\infty]&[^0]&[^1]&[^2]&[^3]&[^4]&[^5]&[^6]\\ \hline 0=[^\infty]&[^\infty]&[^0]&[^1]&[^2]&[^3]&[^4]&[^5]&[^6]\\ 1=[^0]&[^0]&[^\infty]&[^3]&[^6]&[^1]&[^5]&[^4]&[^2]\\ \bar t=[^1]&[^1]&[^3]&[^\infty]&[^4]&[^0]&[^2]&[^6]&[^5]\\ \bar t^2=[^2]&[^2]&[^6]&[^4]&[^\infty]&[^5]&[^1]&[^3]&[^0]\\ \bar t^3=[^3]&[^3]&[^1]&[^0]&[^5]&[^\infty]&[^6]&[^2]&[^4]\\ \bar t^4=[^4]&[^4]&[^5]&[^2]&[^1]&[^6]&[^\infty]&[^0]&[^3]\\ \bar t^5=[^5]&[^5]&[^4]&[^6]&[^3]&[^2]&[^0]&[^\infty]&[^1]\\ \bar t^6=[^6]&[^6]&[^2]&[^5]&[^0]&[^4]&[^3]&[^1]&[^\infty]\\ \end{array} $ \end{center} } {\footnotesize \begin{center} $ \begin{array}{r|cccccccc} \times&[^\infty]&[^0]&[^1]&[^2]&[^3]&[^4]&[^5]&[^6]\\ \hline 0=[^\infty]&[^\infty]&[^\infty]&[^\infty]&[^\infty]&[^\infty]&[^\infty]&[^\infty]&[^\infty]\\ 1=[^0]&[^\infty]&[^0]&[^1]&[^2]&[^3]&[^4]&[^5]&[^6]\\ \bar t=[^1]&[^\infty]&[^1]&[^2]&[^3]&[^4]&[^5]&[^6]&[^0]\\ \bar t^2=[^2]&[^\infty]&[^2]&[^3]&[^4]&[^5]&[^6]&[^0]&[^1]\\ \bar t^3=[^3]&[^\infty]&[^3]&[^4]&[^5]&[^6]&[^0]&[^1]&[^2]\\ \bar t^4=[^4]&[^\infty]&[^4]&[^5]&[^6]&[^0]&[^1]&[^2]&[^3]\\ \bar t^5=[^5]&[^\infty]&[^5]&[^6]&[^0]&[^1]&[^2]&[^3]&[^4]\\ \bar t^6=[^6]&[^\infty]&[^6]&[^0]&[^1]&[^2]&[^3]&[^4]&[^5]\\ \end{array} $ \end{center} } Correspondance (log discret) : \begin{center} $ \begin{array}{c|c|c|c|c|c|c|c} 0&1&\bar t&\bar t+1&\bar t^2&\bar t^2+1&\bar t^2+\bar t&\bar t^2+\bar t+1\\ \hline \{0\}&\{1\}&\{2\}&\{3\}&\{4\}&\{5\}&\{6\}&\{7\}\\ \hline [^\infty]&[^0]&[^1]&[^3]&[^2]&[^6]&[^4]&[^5]\\ \hline 0&1&\bar t&\bar t^3&\bar t^2&\bar t^6&\bar t^4&\bar t^5 \end{array} $ \end{center} % % % \end{document}