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Viewing Version 5 of 'Davenport-Schmidt theorem'
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Title of object: Davenport-Schmidt theorem
Canonical Name: DavenportSchmidt
Type: Theorem

Created on: 2003-04-04 20:04:23
Modified on: 2004-02-07 22:47:17

Creator: Daume
Modifier: Daume
Author: Daume

Classification: msc:11J68

Preamble:

% 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
Content:

For any real $\xi$ which is not rational or quadratic irrational, there are infinitely many rational or real quadratic irrational $\alpha$ which satisfy
\begin{displaymath}
\mid \xi - \alpha \mid < C\cdot H(\alpha)^{-3},
\end{displaymath}
where
\begin{displaymath}
C = \left\{
\begin{array}{ll}
C_0, & \textrm{if} \mid\xi\mid < 1, \\
C_0\cdot \xi^2, & \textrm{if} \mid\xi\mid >1.
\end{array}\right.
\end{displaymath}
$C_0$ is any fixed number greater than $\frac{160}{9}$ and $H(\alpha )$ is the \PMlinkescapetext{height} of $\alpha$.
\begin{thebibliography}{1}
\bibitem{DS} Davenport, H. Schmidt, M. Wolfgang: Approximation to real numbers by quadratic irrationals. Acta Arithmetica XIII, 1967.
\end{thebibliography}