Abstract:
Let $G$ be a finite group. A subgroup $A$ is called:
1) $S$-quasinormal in $G$ if $A$ is permutable with all Sylow subgroups in $G$
2) $S$-quasinormally embedded in $G$ if every Sylow subgroup of $A$ is a Sylow subgroup of some
$S$-quasinormal subgroup of $G$. Let $B_{seG}$ be the subgroup generated by all the
subgroups of $B$ which are
$S$-quasinormally embedded in $G$.
A subgroup $B$ is called $SE$-supplemented in $G$ if there exists a
subgroup $T$ such that $G=BT$ and
$B\cap T\le B_{seG}$. The main result of the paper is the
following.
Theorem.Let $H$ be a normal subgroup in $G$, and $p$
a prime divisor of $|H|$ such that $(p-1,|H|)=1$.
Let $P$ be a Sylow $p$-subgroup in $H$. Assume
that all maximal subgroups in $P$ are $SE$-supplemented in $G$. Then $H$
is $p$-nilpotent and all its $G$-chief $p$-factors are cyclic.