principal congruence subgroup

Subgroups with finite index of a Hecke group, which are called congruence subgroup, are often used in researching Dirichlet series, so it is necessary to investigate their structure.

Hecke群的有限指数的子群(称这些子群为Hecke群的同余子群)同样在研究Dirichlet级数发挥了重要作用,调查这些子群的结构是非常必要的。

Essential subgroups and superfluous subgroups of a group;

群的本质子群和多余子群

In this paper, some results on the superfluous subgroups of a finitely-generated infinite soluble group are obtained, which are the generalizations of the corresponding results of a finite group.

本文得到了有限生成的无限可解群的多余子群的一些结果,它们是有限群的某些相应结果的推广。

Let G be an l-group, T is the largest superfluous convex l-subgroup of G.

设G是一个l-群,T是G的最大的多余凸l-子群。