Lecture Notes on Bayesian Estimation and Classification
《Lecture Notes on Bayesian Estimation and Classification》 · 第 54 页 · Section 2.2「Presentations of Groups」
For example, if a group $G$ has a chain of subgroups $1=G_0\triangleleft G_1\triangleleft\cdots\triangleleft G_i\triangleleft G_{i+1}\triangleleft\cdots\triangleleft G_n=G$ in which each $G_{i+1}/G_i$ is cyclic, then $G$ is finitely presented. Such groups are called polycyclic: they are studied in Chapters 5 and 15.