Solitons: Differential equations, symmetries, and infinite-dimensional algebras
《Solitons: Differential equations, symmetries, and infinite-dimensional algebras》 · 第 86 页 · Definition 3.41(1)
A closed subscheme of $X$ is given by a closed subset $Z\subseteq X$ and an ideal sheaf $\mathcal J\subseteq\mathcal O_X$ such that $Z=\{x\in X;(\mathcal O_X/\mathcal J)_x\ne0\}$ and $(Z,(\mathcal O_X/\mathcal J)|_Z)$ is a scheme.