English

Random subgroups of branch groups

Group Theory 2025-08-28 v1

Abstract

We show that independent Haar-random elements in a super strongly fractal branch profinite group generate a free subgroup acting freely on the boundary of the tree. This improves a previous result of Ab\'ert (2005) for weakly branch profinite groups, where independent random elements were shown to generate free subgroups acting only almost freely on the boundary. Our result also generalizes the analogous result of Ab\'ert and Vir\'ag (2005) for iterated wreath products.

Cite

@article{arxiv.2508.20082,
  title  = {Random subgroups of branch groups},
  author = {Jorge Fariña-Asategui and Santiago Radi},
  journal= {arXiv preprint arXiv:2508.20082},
  year   = {2025}
}

Comments

15 pages

R2 v1 2026-07-01T05:08:50.632Z