给出一个拟左群同构于拟群和左零带的直积的一个充分必要条件,同时给出了左群的收缩诣零扩张的一个刻画。
This paper obtains a necessary and sufficient condition for a quasi-left group to be isomorphic to a direct product of a quasi-group and a left zero band.Furthermore, a retract nil-extensions of a left group is also characterized.