English

On $\sigma$-arithmetic graphs of finite groups

Group Theory 2020-01-27 v1

Abstract

Let GG be a finite group and σ\sigma a partition of the set of all? primes P\Bbb{P}, that is, σ={σiiI}\sigma =\{\sigma_i \mid i\in I \}, where P=iIσi\Bbb{P}=\bigcup_{i\in I} \sigma_i and σiσj=\sigma_i\cap \sigma_j= \emptyset for all iji\ne j. If nn is an integer, we write σ(n)={σiσiπ(n)}\sigma(n)=\{\sigma_i \mid \sigma_{i}\cap \pi (n)\ne \emptyset \} and σ(G)=σ(G)\sigma (G)=\sigma (|G|). We call a graph Γ\Gamma with the set of all vertices V(Γ)=σ(G)V(\Gamma)=\sigma (G) (G1G\ne 1) a σ\sigma-arithmetic graph of GG, and we associate with G1G\ne 1 the following three directed σ\sigma-arithmetic graphs: (1) the σ\sigma-Hawkes graph ΓHσ(G)\Gamma_{H\sigma }(G) of GG is a σ\sigma-arithmetic graph of GG in which (σi,σj)E(ΓHσ(G))(\sigma_i, \sigma_j)\in E(\Gamma_{H\sigma }(G)) if σjσ(G/F{σi}(G))\sigma_j\in \sigma (G/F_{\{\sigma_i\}}(G)); (2) the σ\sigma-Hall graph ΓσHal(G)\Gamma_{\sigma Hal}(G) of GG in which (σi,σj)E(ΓσHal(G))(\sigma_i, \sigma_j)\in E(\Gamma_{\sigma Hal}(G)) if for some Hall σi\sigma_i-subgroup HH of GG we have σjσ(NG(H)/HCG(H))\sigma_j\in \sigma (N_{G}(H)/HC_{G}(H)); (3) the σ\sigma-Vasil'ev-Murashko graph ΓNσ(G)\Gamma_{{\mathfrak{N}_\sigma }}(G) of GG in which (σi,σj)E(ΓNσ(G))(\sigma_i, \sigma_j)\in E(\Gamma_{{\mathfrak{N}_\sigma}}(G)) if for some Nσ{\mathfrak{N}_{\sigma }}-critical subgroup HH of GG we have σiσ(H)\sigma_i \in \sigma (H) and σjσ(H/F{σi}(H))\sigma_j\in \sigma (H/F_{\{\sigma_i\}}(H)). In this paper, we study the structure of GG depending on the properties of these three graphs of GG.

Keywords

Cite

@article{arxiv.2001.09147,
  title  = {On $\sigma$-arithmetic graphs of finite groups},
  author = {Alexander N. Skiba},
  journal= {arXiv preprint arXiv:2001.09147},
  year   = {2020}
}
R2 v1 2026-06-23T13:20:11.672Z