Geodesic continued fractions and LLL

Abstract

We discuss a proposal for a continued fraction-like algorithm to determine simultaneous rational approximations to $d$ real numbers $\alpha_1,\ldots,\alpha_d$. It combines an algorithm of Hermite and Lagarias with ideas from LLL-reduction. We dynamically LLL-reduce a quadratic form with parameter $t$ as $t\downarrow0$. The new idea in this paper is that checking the LLL-conditions consists of solving linear equations in $t$.