Lemma 63.39.5. An étale morphism of algebraic spaces is locally quasi-finite.
Proof. Let $X \to Y$ be an étale morphism of algebraic spaces, see Properties of Spaces, Definition 62.16.2. By Properties of Spaces, Lemma 62.16.3 we see this means there exists a diagram as in Lemma 63.22.1 with $h$ étale and surjective vertical arrow $a$. By Morphisms, Lemma 28.34.6 $h$ is locally quasi-finite. Hence $X \to Y$ is locally quasi-finite by definition. $\square$
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