Commensurators of normal subgroups of lattices
Group Theory
2023-05-30 v3 Geometric Topology
Abstract
We study a question of Greenberg-Shalom concerning arithmeticity of discrete subgroups of semisimple Lie groups with dense commensurators. We answer this question positively for normal subgroups of lattices. This generalizes a result of the second author and T. Koberda for certain normal subgroups of arithmetic lattices in SO(n,1) and SU(n,1).
Cite
@article{arxiv.2202.04027,
title = {Commensurators of normal subgroups of lattices},
author = {David Fisher and Mahan Mj and Wouter Van Limbeek},
journal= {arXiv preprint arXiv:2202.04027},
year = {2023}
}