English

Congruence RFRS towers

Geometric Topology 2019-12-24 v1 Group Theory Number Theory

Abstract

We describe a criterion for a real or complex hyperbolic lattice to admit a RFRS tower that consists entirely of congruence subgroups. We use this to show that certain Bianchi groups PSL(Od)\mathrm{PSL}(\mathcal{O}_d) are virtually fibered on congruence subgroups, and also exhibit the first examples of RFRS K\"ahler groups that are not a subgroup of a product of surface groups and abelian groups.

Keywords

Cite

@article{arxiv.1912.10283,
  title  = {Congruence RFRS towers},
  author = {Ian Agol and Matthew Stover},
  journal= {arXiv preprint arXiv:1912.10283},
  year   = {2019}
}

Comments

With an appendix by Mehmet Haluk \c{S}eng\"un

R2 v1 2026-06-23T12:53:26.191Z