English

The virtually generating graph of a profinite group

Group Theory 2023-06-22 v1

Abstract

We consider the graph Γvirt(G)\Gamma_{\rm{virt}}(G) whose vertices are the elements of a finitely generated profinite group GG and where two vertices xx and yy are adjacent if and only if they topologically generate an open subgroup of GG. We investigate the connectivity of the graph Δvirt(G)\Delta_{\rm{virt}}(G) obtained from Γvirt(G)\Gamma_{\rm{virt}}(G) by removing its isolated vertices. In particular we prove that for every positive integer tt, there exists a finitely generated prosoluble group GG with the property that Δvirt(G)\Delta_{\rm{virt}}(G) has precisely tt connected components. Moreover we study the graph Γ~virt(G)\tilde \Gamma_{\rm{virt}}(G), whose vertices are again the elements of GG and where two vertices are adjacent if and only if there exists a minimal generating set of GG containing them. In this case we prove that the subgraph Δ~virt(G)\tilde \Delta_{\rm{virt}}(G) obtained removing the isolated vertices is connected and has diameter at most 3.

Keywords

Cite

@article{arxiv.2007.12478,
  title  = {The virtually generating graph of a profinite group},
  author = {Andrea Lucchini},
  journal= {arXiv preprint arXiv:2007.12478},
  year   = {2023}
}
R2 v1 2026-06-23T17:22:30.273Z