The influence of weakly $SΦ$-supplemented subgroups on fusion systems of finite groups

Shengmin Zhang, Zhencai Shen

Published 2023-12-26, updated 2024-02-06Version 2

Let $G$ be a finite group and $H$ be a subgroup of $G$. Then $H$ is called a weakly $S\Phi$-supplemented subgroup of $G$, if there exists a subgroup $T$ of $G$ such that $G =HT$ and $H \cap T \leq \Phi (H) H_{sG}$, where $H_{sG}$ denotes the subgroup of $H$ generated by all subgroups of $H$ which are $S$-permutable in $G$. Let $p$ be a prime, $S$ be a $p$-group and $\mathcal{F}$ be a saturated fusion system over $S$. Then $\mathcal{F}$ is said to be supersolvable, if there exists a series of $S$, namely $1 = S_0 \leq S_1 \leq \cdots \leq S_n = S$, such that $S_{i+1}/S_i$ is cyclic, $i=0,1,\cdots, n-1$, $S_i$ is strongly $\mathcal{F}$-closed, $i=0,1,\cdots,n$. In this paper, we investigate the structure of fusion system $\mathcal{F}_S (G)$ under the assumption that certain subgroups of $S$ are weakly $S\Phi$-supplemented in $G$, and obtain several new characterizations of supersolvability of $\mathcal{F}_S (G)$.