The Stacks project

Definition 67.27.1. Let $S$ be a scheme. Let $f : X \to Y$ be a morphism of algebraic spaces over $S$.

1. We say $f$ is locally quasi-finite if the equivalent conditions of Lemma 67.22.1 hold with $\mathcal{P} = \text{locally quasi-finite}$.

2. Let $x \in |X|$. We say $f$ is quasi-finite at $x$ if there exists an open neighbourhood $X' \subset X$ of $x$ such that $f|_{X'} : X' \to Y$ is locally quasi-finite.

3. A morphism of algebraic spaces $f : X \to Y$ is quasi-finite if it is locally quasi-finite and quasi-compact.