First Page.

Finite Morphisms

Definition: A morphism of rings φ:A⟶B\varphi \colon A \longrightarrow B is called finite, if BB is finitely generated as an -module, that is, there is an epimorphism of -modules

A⊕︎n↠BA^{\oplus n} \twoheadrightarrow B

for some n∈ℕn \in \mathbb{N}.

Fact: Finite morphisms are affine.

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