Counting lattices in products of trees

Nir Lazarovich, Ivan Levcovitz, Alex Margolis

Research output: Contribution to journalArticlepeer-review

Abstract

A BMW group of degree .m; n/ is a group that acts simply transitively on vertices of the product of two regular trees of degrees m and n. We show that the number of commensurability classes of BMW groups of degree .m; n/ is bounded between .mn/αmn and .mn/βmn for some 0 < α < β. In fact, we show that the same bounds hold for virtually simple BMW groups. We introduce a random model for BMW groups of degree .m; n/ and show that asymptotically almost surely a random BMW group in this model is irreducible and hereditarily just-infinite.

Original languageEnglish
Pages (from-to)597-630
Number of pages34
JournalCommentarii Mathematici Helvetici
Volume98
Issue number3
DOIs
StatePublished - 2023

Keywords

  • CAT(0) square complexes
  • Lattices
  • product of trees
  • random complexes
  • simple groups

All Science Journal Classification (ASJC) codes

  • General Mathematics

Cite this