In this paper, we study finite groups all of whose nontrivial normal subgroups have the same order. In the solvable case, the groups are determined. In the insolvable case, some characterizations are given.
基金the National Natural Science Foundation of China (No.10671114)the Natural Science Foun-dation of Shanxi Province (No.20051007)the Returned Abroad-student Fund of Shanxi Province (No.[2004]13-56)
文摘In this paper, we study finite groups all of whose nontrivial normal subgroups have the same order. In the solvable case, the groups are determined. In the insolvable case, some characterizations are given.
