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Viewing Version 5 of 'rational root theorem'
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Title of object: rational root theorem
Canonical Name: RationalRootTheorem
Type: Theorem

Created on: 2001-10-15 22:12:09
Modified on: 2004-03-30 23:58:01

Creator: drini
Modifier: drini
Author: archibal
Author: drini

Classification: msc:12D05, msc:12D10
Keywords: polynomial

Revision comment (for changes between this and next version):

Changes for correction #6289 ('special case of a result about monic polys??').

Preamble:

\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{graphicx}
\usepackage{xypic}
Content:

\PMlinkescapeword{states}
\PMlinkescapeword{domain}
\PMlinkescapeword{base}
Consider the polynomial
$$p(x)=a_nx^n + a_{n-1}x^{n-1}+\cdots+a_1x+a_0$$
where all the coefficients $a_i$ are integers.

If $p(x)$ has a rational root $p/q$ where $\gcd(p,q)=1$, then
$p| a_0$ and $q| a_n$.

This theorem is a special case of a result about monic polynomials whose coefficients belong to a unique factorization domain. The theorem then states that any root in the fraction field is also in the base domain.