English

Random groups at density $d<3/14$ act non-trivially on a CAT(0) cube complex

Group Theory 2022-08-26 v2

Abstract

For random groups in the Gromov density model at d<3/14d<3/14, we construct walls in the Cayley complex XX which give rise to a non-trivial action by isometries on a CAT(0) cube complex. This extends results of Ollivier-Wise and Mackay-Przytycki at densities d<1/5d<1/5 and d<5/24d<5/24, respectively. We are able to overcome one of the main combinatorial challenges remaining from the work of Mackay-Przytycki, and we give a construction that plausibly works at any density d<1/4d<1/4.

Keywords

Cite

@article{arxiv.2106.14931,
  title  = {Random groups at density $d<3/14$ act non-trivially on a CAT(0) cube complex},
  author = {MurphyKate Montee},
  journal= {arXiv preprint arXiv:2106.14931},
  year   = {2022}
}

Comments

30 pages, 17 figures Several revisions to exposition made based on reviewer comments. Replaced Definition 4.6 with Definition 4.6 and Construction 4.7. Accepted version, to appear in Transactions of the AMS

R2 v1 2026-06-24T03:41:20.359Z