Finite groups and $k$-submodular subgroups
T. I. Vasilyeva
TL;DR
The paper develops a framework for $k$-submodular subgroups in finite groups by introducing $n$-modularly embedded subgroups and $k$-LM-groups as generalizations of classical notions. It formulates a formation-theoretic approach, defines four pivotal classes $\mathfrak{X},\mathfrak{Y},\mathfrak{K},\mathfrak{F}$, and establishes their hierarchical inclusions and equalities $\mathfrak{K}=\mathfrak{U}\cap \mathrm{w}\mathfrak{U}_{k}$ and $\mathfrak{F}=\mathrm{w}\mathfrak{K}$. The main results characterize when all maximal subgroups are $k$-submodular in terms of supersolubility and constrained chief-factor actions, and prove that $LF(h)=\mathfrak{K}$ and related local formations coincide with these classes. These findings extend the theory of submodular/LM-groups and provide a structured classification for finite groups under $k$-submodular subgroup conditions, with implications for the subnormality of Sylow subgroups and the composition structure of groups in these formations.
Abstract
For natural numbers $n$ and $k$, the concepts of $n$-modularly embedded subgroup, $k$-submodular subgroup and $k$-$\mathrm{LM}$-group are given, which generalize, respectively, the concepts of modular subgroup, submodular subgroup and $\mathrm{LM}$-group. Classes of groups with given systems of $k$-submodular subgroups are investigated.
