定义一类极大子群的交Δπ(G),它是Δ(G)的推广.给出了类似于Δ(G)的基本性质,并给出了Δπ(G)π-幂零性,π-超可解性与群G的π-幂零性,π-超可解性的充要条件.
In this paper,a generalize of Δπ(G) is defined,which is defined to be the intersection of a class of the maximal subgroups of Δπ(G).Not only some basic properties of ΔG,but also some necessary and sufficient conditions among the properties of π-nilpotent、 π-supersoluble of G and the properties of π-nilpotent、π-supersoluble of Δπ(G) are all given.