Cohomologie Locale Des Faisceaux Coherents (Sga 2): Seminaire De Geometrie Algebrique Du Bois Marie 1962 (Documents Mathematiques)
《Cohomologie Locale Des Faisceaux Coherents (Sga 2): Seminaire De Geometrie Algebrique Du Bois Marie 1962 (Documents Mathematiques)》 · 第 104–105 页 · Chapter 6，Section 6.3「Radicals, Socles, and the Augmentation Ideal」
...and these submodules of $U$ form chains, $\dots \subseteq \operatorname{Rad}^2 U \subseteq \operatorname{Rad} U \subseteq U$, $0 \subseteq \operatorname{Soc} U \subseteq \operatorname{Soc}^2 U \subseteq \dots$, that are called, respectively, the radical series and socle series of $U$. The radical series of $U$ is also known as the Loewy series of $U$.