English

Coprime commutators in profinite groups

Group Theory 2026-04-08 v2

Abstract

By a coprime commutator in a profinite group GG we mean any element of the form [x,y][x, y], where x,yGx,y\in G and (x,y)=1(|x|,|y|)=1. It is well-known that the subgroup generated by the coprime commutators of GG is precisely the pronilpotent residual γ(G)\gamma_\infty(G). There are several recent works showing that finiteness conditions on the set of coprime commutators have strong impact on the properties of γ(G)\gamma_\infty(G) and, more generally, on the structure of GG. In this paper we show that if the set of coprime commutators of a profinite group GG is covered by countably many procyclic subgroups, then γ(G)\gamma_\infty(G) is finite-by-procyclic. In particular, it follows that GG is finite-by-pronilpotent-by-abelian.

Keywords

Cite

@article{arxiv.2510.03754,
  title  = {Coprime commutators in profinite groups},
  author = {Cristina Acciarri and Pavel Shumyatsky},
  journal= {arXiv preprint arXiv:2510.03754},
  year   = {2026}
}

Comments

24 pages, revised version, to appear in Revista Matem\'atica Complutense

R2 v1 2026-07-01T06:16:59.087Z