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arXiv · 1303.0584

Univalent categories and the Rezk completion

Benedikt Ahrens·Chris Kapulkin·Michael Shulman
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Abstract

We develop category theory within Univalent Foundations, which is a foundational system for mathematics based on a homotopical interpretation of dependent type theory. In this system, we propose a definition of "category" for which equality and equivalence of categories agree. Such categories satisfy a version of the Univalence Axiom, saying that the type of isomorphisms between any two objects is equivalent to the identity type between these objects; we call them "saturated" or "univalent" categories. Moreover, we show that any category is weakly equivalent to a univalent one in a universal way. In homotopical and higher-categorical semantics, this construction corresponds to a truncated version of the Rezk completion for Segal spaces, and also to the stack completion of a prestack.

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Benedikt Ahrens, Chris Kapulkin, Michael Shulman. 2014-01-06. Univalent categories and the Rezk completion. https://doi.org/10.1017/s0960129514000486

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