Special subgroups of Bianchi groups
Group Theory
2020-10-28 v1 Geometric Topology
Abstract
We determine C-special subgroups of the Bianchi groups of index bounded above by 120 by effectivising the arguments of Agol-Long-Reid. These subgroups are congruence of level 2 or 4 and retract to the free group on two generators. As a consequence, we find a C-special 20-sheeted cover of the figure-eight knot complement. We also determine C-special congruence subgroups for a family of cocompact arithmetic Kleinian groups.
Cite
@article{arxiv.1709.10503,
title = {Special subgroups of Bianchi groups},
author = {Michelle Chu},
journal= {arXiv preprint arXiv:1709.10503},
year = {2020}
}
Comments
14 pages