English

Cyclic hyperbolicity in CAT(0) cube complexes

Group Theory 2025-04-22 v3 Metric Geometry

Abstract

It is known that a cocompact special group GG does not contain Z×Z\mathbb{Z} \times \mathbb{Z} if and only if it is hyperbolic; and it does not contain F2×Z\mathbb{F}_2 \times \mathbb{Z} if and only if it is toric relatively hyperbolic. Pursuing in this direction, we show that GG does not contain F2×F2\mathbb{F}_2 \times \mathbb{F}_2 if and only if it is weakly hyperbolic relative to cyclic subgroups, or cyclically hyperbolic for short. This observation motivates the study of cyclically hyperbolic groups, which we initiate in the class of groups acting geometrically on CAT(0) cube complexes. Given such a group GG, we first prove a structure theorem: GG virtually splits as the direct sum of a free abelian group and an acylindrically hyperbolic cubulable group. Next, we prove a strong Tits alternative: every subgroup HGH \leq G either is virtually abelian or it admits a series H=H0H1HkH=H_0 \rhd H_1 \rhd \cdots \rhd H_k where HkH_k is acylindrically hyperbolic and where Hi/Hi+1H_i/H_{i+1} is finite or free abelian. As a consequence, GG is SQ-universal and it cannot contain subgroups such that products of free groups and virtually simple groups.

Keywords

Cite

@article{arxiv.2109.07186,
  title  = {Cyclic hyperbolicity in CAT(0) cube complexes},
  author = {Anthony Genevois},
  journal= {arXiv preprint arXiv:2109.07186},
  year   = {2025}
}

Comments

37 pages, 7 figures. Final version. To appear in Fundamenta Mathematicae

R2 v1 2026-06-24T05:58:57.417Z