Published online by Cambridge University Press: 18 July 2019
Given a positive integer $m$, a finite
$p$-group
$G$ is called a
$BC(p^{m})$-group if
$|H_{G}|\leq p^{m}$ for every nonnormal subgroup
$H$ of
$G$, where
$H_{G}$ is the normal core of
$H$ in
$G$. We show that
$m+2$ is an upper bound for the nilpotent class of a finite
$BC(p^{m})$-group and obtain a necessary and sufficient condition for a
$p$-group to be of maximal class. We also classify the
$BC(p)$-groups.
This work was supported by the National Natural Science Foundation of China (11671324, 11471266).