On $H_σ$-permutably embedded and $H_σ$-subnormaly embedded subgroups of finite groups (1701.05134v1)

Abstract: Let $G$ be a finite group. Let $\sigma ={\sigma_{i} | i\in I}$ be a partition of the set of all primes $\Bbb{P}$ and $n$ an integer. We write $\sigma (n) ={\sigma_{i} |\sigma_{i}\cap \pi (n)\ne \emptyset }$, $\sigma (G) =\sigma (|G|)$. A set $ {\cal H}$ of subgroups of $G$ is said to be a complete Hall $\sigma $-set of $G$ if every member of ${\cal H}\setminus {1}$ is a Hall $\sigma_{i}$-subgroup of $G$ for some $\sigma_{i}$ and ${\cal H}$ contains exact one Hall $\sigma_{i}$-subgroup of $G$ for every $\sigma_{i}\in \sigma (G)$. A subgroup $A$ of $G$ is called: (i) a $\sigma$-Hall subgroup of $G$ if $\sigma (|A|) \cap \sigma (|G:A|)=\emptyset$; (ii) ${\sigma}$-permutable in $G$ if $G$ possesses a complete Hall $\sigma$-set ${\cal H}$ such that $AH^{x}=H^{x}A$ for all $H\in {\cal H}$ and all $x\in G$. We say that a subgroup $A$ of $G$ is $H_{\sigma}$-permutably embedded in $G$ if $A$ is a ${\sigma}$-Hall subgroup of some ${\sigma}$-permutable subgroup of $G$. We study finite groups $G$ having an $H_{\sigma}$-permutably embedded subgroup of order $|A|$ for each subgroup $A$ of $G$. Some known results are generalized.