On weakly σ-semipermutable subgroups of finite groups
Let [Formula: see text] be some partition of the set of all primes [Formula: see text], [Formula: see text] be a finite group and [Formula: see text]. A set [Formula: see text] of subgroups of [Formula: see text] is said to be a complete Hall[Formula: see text]-set of [Formula: see text] if every non-identity member of [Formula: see text] is a Hall [Formula: see text]-subgroup of [Formula: see text] for some [Formula: see text] and [Formula: see text] contains exactly one Hall [Formula: see text]-subgroup of [Formula: see text] for every [Formula: see text]. Let [Formula: see text] be a complete Hall [Formula: see text]-set of [Formula: see text]. A subgroup [Formula: see text] of [Formula: see text] is said to be [Formula: see text]-semipermutable with respect to [Formula: see text] if [Formula: see text] for all [Formula: see text] and all [Formula: see text] such that [Formula: see text]; [Formula: see text]-semipermutablein [Formula: see text] if [Formula: see text] is [Formula: see text]-semipermutable in [Formula: see text] with respect to some complete Hall [Formula: see text]-set of [Formula: see text]. We say that a subgroup [Formula: see text] of [Formula: see text] is weakly[Formula: see text]-semipermutable in [Formula: see text] if there exists a [Formula: see text]-permutable subgroup [Formula: see text] of [Formula: see text] such that [Formula: see text] is [Formula: see text]-permutable in [Formula: see text] and [Formula: see text], where [Formula: see text] is the subgroup of [Formula: see text] generated by all those subgroups of [Formula: see text] which are [Formula: see text]-semipermutable in [Formula: see text]. In this paper, we study the structure of [Formula: see text] under the condition that some subgroups of [Formula: see text] are weakly [Formula: see text]-semipermutable in [Formula: see text].