English

Hyperbolic groups that are not commensurably coHopfian

Group Theory 2020-02-19 v3 Geometric Topology

Abstract

Sela proved every torsion-free one-ended hyperbolic group is coHopfian. We prove that there exist torsion-free one-ended hyperbolic groups that are not commensurably coHopfian. In particular, we show that the fundamental group of every simple surface amalgam is not commensurably coHopfian.

Keywords

Cite

@article{arxiv.1812.07799,
  title  = {Hyperbolic groups that are not commensurably coHopfian},
  author = {Emily Stark and Daniel J. Woodhouse},
  journal= {arXiv preprint arXiv:1812.07799},
  year   = {2020}
}

Comments

v3: 14 pages, 4 figures; minor changes. To appear in International Mathematics Research Notices

R2 v1 2026-06-23T06:47:25.164Z