DirichletsTheorem 2002-02-16 02:18:04 2002-05-07 05:17:36 Theorem Dirichlet Prime % this is the default PlanetMath preamble. as your knowledge % of TeX increases, you will probably want to edit this, but % it should be fine as is for beginners. % almost certainly you want these \usepackage{amssymb} \usepackage{amsmath} \usepackage{amsfonts} % used for TeXing text within eps files %\usepackage{psfrag} % need this for including graphics (\includegraphics) %\usepackage{graphicx} % for neatly defining theorems and propositions %\usepackage{amsthm} % making logically defined graphics %\usepackage{xypic} % there are many more packages, add them here as you need them % define commands here If $a$ is a positive integer and $(a,b)=1$, with $b$ an integer, then there are infinitely many primes of the form $an + b$, with $n$ an integer.