Lecture Notes on Bayesian Estimation and Classification
《Lecture Notes on Bayesian Estimation and Classification》 · 第 87 页 · Section 3.3「Direct Decompositions」
The subgroup generated by all the minimal normal subgroups of a group $G$ is called the socle: should the group fail to have any minimal normal subgroups, as in the case of the infinite cyclic group for example, the socle of $G$ is defined to be $1$.