Let G be an infinite group. If G has a normal elementary abelian subgroup, then G is irrecognizable.

G无限群,若G存在正规初等交换子群,则G不可分辨的.

Considering the subnormal subgroups,some equivalent conditions for nilpotency of finite groups are given and a sufficient condition for nilpotency of finite groups is obtained.

研究次正规子群对有限群结构的影响,到幂零群的若干等价条件和一个充分条件。