Equidistribution of divergent diagonal orbits in positive characteristic

Fuente: arXiv
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Main Authors: Dang, Nguyen-Thi, Paulin, Frédéric, Sayous, Rafael
Format: Preprint
Published: 2025
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author Dang, Nguyen-Thi
Paulin, Frédéric
Sayous, Rafael
author_facet Dang, Nguyen-Thi
Paulin, Frédéric
Sayous, Rafael
contents Given a local field $\widehat K$ with positive characteristic, we study the dynamics of the diagonal subgroup of the linear group $\operatorname{GL}_n(\widehat K)$ on homogeneous spaces of discrete lattices in ${\widehat K}^{\,n}$. We first give a function field version of results by Margulis and Tomanov-Weiss, characterizing the divergent diagonal orbits. When $n=2$, we relate the divergent diagonal orbits with the divergent orbits of the geodesic flow in the modular quotient of the Bruhat-Tits tree of $\operatorname{PGL}_2(\widehat K)$. Using the (high) entropy method by Einsiedler-Lindentraus et al, we then give a function field version of a result of David-Shapira on the equidistribution of a natural family of these divergent diagonal orbits, with height given by a new notion of discriminant of the orbits.
format Preprint
id arxiv_https___arxiv_org_abs_2503_13995
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Equidistribution of divergent diagonal orbits in positive characteristic
Dang, Nguyen-Thi
Paulin, Frédéric
Sayous, Rafael
Number Theory
Dynamical Systems
Group Theory
22F30, 11N45, 20G30, 14G17, 28C10, 11J70, 11P21
Given a local field $\widehat K$ with positive characteristic, we study the dynamics of the diagonal subgroup of the linear group $\operatorname{GL}_n(\widehat K)$ on homogeneous spaces of discrete lattices in ${\widehat K}^{\,n}$. We first give a function field version of results by Margulis and Tomanov-Weiss, characterizing the divergent diagonal orbits. When $n=2$, we relate the divergent diagonal orbits with the divergent orbits of the geodesic flow in the modular quotient of the Bruhat-Tits tree of $\operatorname{PGL}_2(\widehat K)$. Using the (high) entropy method by Einsiedler-Lindentraus et al, we then give a function field version of a result of David-Shapira on the equidistribution of a natural family of these divergent diagonal orbits, with height given by a new notion of discriminant of the orbits.
title Equidistribution of divergent diagonal orbits in positive characteristic
topic Number Theory
Dynamical Systems
Group Theory
22F30, 11N45, 20G30, 14G17, 28C10, 11J70, 11P21
url https://arxiv.org/abs/2503.13995