Joint equidistribution of approximates

Gaurav Aggarwal, Anish Ghosh

Published 2024-01-05Version 1

We consider the joint asymptotic distribution of \emph{best} and $\varepsilon$ Diophantine approximates of matrices in several aspects. Our main results describe the resulting limiting measures for almost every matrix. Multiplicative Diophantine approximation is treated for the first time in this context and a number of Diophantine corollaries are derived including a matrix L\'{e}vy-Khintchine type theorem. While we treat the general case of approximation of matrices, our results are already new for the case of simultaneous Diophantine approximation of vectors. Our approach is dynamical and is inspired by work of several authors, notably Shapira and Weiss. It is based on the construction of an appropriate Poincar\'{e} section for certain diagonal group actions on the space of unimodular lattices. The main new idea in our paper is a method which allows us to treat actions of higher rank groups.