Lecture Notes on Bayesian Estimation and Classification
《Lecture Notes on Bayesian Estimation and Classification》 · 第 384 页 · Section 12.5「Locally Soluble Groups」，Exercises 12.5，题 4
If $G$ is a locally soluble group with max-n, some term of the (transfinitely extended) derived series equals 1. (Such groups are called hypoabelian.)