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Revision difference : Davenport-Schmidt theorem
Version 4 Version 3
For any real $\xi$ which is not rational or quadratic irrational, there are infinitely many rational or real quadratic irrational $\alpha$ which satisfy 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} \begin{displaymath}
\mid \xi - \alpha \mid < C\cdot H(\alpha)^{-3}, \mid \xi - \alpha \mid < C\cdot H(\alpha)^{-3},
\end{displaymath} \end{displaymath}
where where
\begin{displaymath} \begin{displaymath}
C = \left\{ C = \left\{
\begin{array}{ll} \begin{array}{ll}
C_0, & \textrm{if} \mid\xi\mid < 1, \\ C_0, & \textrm{if} \mid\xi\mid < 1, \\
C_0\cdot \xi^2, & \textrm{if} \mid\xi\mid >1. C_0\cdot \xi^2, & \textrm{if} \mid\xi\mid >1.
\end{array}\right \end{array}\right
\end{displaymath} \end{displaymath}
$C_0$ is any fixed number greater than $\frac{160}{9}$ and $H(\alpha )$ is the \PMlinkescapetext{height} of $\alpha$. $C_0$ is any fixed number greater than $\frac{160}{9}$ and $H(\alpha )$ is the \PMlinkescapetext{height} of $\alpha$.
\begin{thebibliography}{1} \begin{thebibliography}{1}
\bibitem{DS} Davenport, H. Schmidt, M. Wolfgang: Approximation to real numbers by quadratic irrationals. Acta Arithmetica XIII, 1967. \bibitem{DS} Davenport, H. & Schmidt, M. Wolfgang: Approximation to real numbers by quadratic irrationals. Acta Arithmetica XIII, 1967.
\end{thebibliography} \end{thebibliography}