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Main Author: de Brecht, Matthew
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.27466
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author de Brecht, Matthew
author_facet de Brecht, Matthew
contents An étale space over a topological space $Y$ is defined as a local homeomorphism from a topological space $X$ into $Y$. They often come up in topos theory because of the equivalence between sheaves and étale spaces over a space. In this note, we define computable étale spaces over a computable topological space $Y$ within the TTE framework of computable topology, and show they are naturally equivalent to computable functions from $Y$ to $\mathsf{ODS}$, the effective quasi-Polish category of overt-discrete quasi-Polish spaces. More generally, if $\cal C$ is a computable category (or groupoid), then there is an equivalence between computable functors from $\cal C$ to $\mathsf{ODS}$, and computable étale spaces equipped with a computable action by $\cal C$.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27466
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A note on computable étale spaces
de Brecht, Matthew
Logic
Category Theory
An étale space over a topological space $Y$ is defined as a local homeomorphism from a topological space $X$ into $Y$. They often come up in topos theory because of the equivalence between sheaves and étale spaces over a space. In this note, we define computable étale spaces over a computable topological space $Y$ within the TTE framework of computable topology, and show they are naturally equivalent to computable functions from $Y$ to $\mathsf{ODS}$, the effective quasi-Polish category of overt-discrete quasi-Polish spaces. More generally, if $\cal C$ is a computable category (or groupoid), then there is an equivalence between computable functors from $\cal C$ to $\mathsf{ODS}$, and computable étale spaces equipped with a computable action by $\cal C$.
title A note on computable étale spaces
topic Logic
Category Theory
url https://arxiv.org/abs/2604.27466