Solitons: Differential equations, symmetries, and infinite-dimensional algebras
《Solitons: Differential equations, symmetries, and infinite-dimensional algebras》 · 第 85 页 · Definition 3.40
A morphism $j:Y\to X$ of schemes is called an open immersion if the underlying continuous map is a homeomorphism of $Y$ with an open subset $U$ of $X$, and the sheaf homomorphism $\mathcal O_X\to j_*\mathcal O_Y$ induces an isomorphism $\mathcal O_X|_U\cong(j_*\mathcal O_Y)|_U$.