群G的一个子群H称为在G中具有半覆盖远离性,如果存在G的一个主群列1=G0〈G1〈…〈Gl=G,使得对每一个j=1,2,…,l,或者H覆盖Gj/Gj-1,或者H远离Gj/Gj-1.利用极小子群及4阶循环子群具有半覆盖远离性的性质,得到一些新的关于有限群为幂零群或超可解群的充分必要条件,推广了以前的结论.
A subgroup H is said to be semi-cover-avoiding in a group G if there is a chief series 1=G0G1…Gl=G such that for every j=1,2,…,l,either H covers Gj/Gj-1 or H avoids Gj/Gj-1.In this paper,some new necessary and sufficient conditions for a finite group G to be nilponent or supersolvable are given by using minimal subgroups and cyclic subgroups of order 4 with semi-cover-avoiding property in the group.Some known results are generalized.