Dagger categories of relations: The equivalence of dilatory dagger categories and epi-regular independence categories

Fuente: arXiv
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Main Authors: Di Meglio, Matthew, Heunen, Chris, Lemay, Jean-Simon Pacaud, Perrone, Paolo, Stein, Dario
Format: Preprint
Published: 2025
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_version_ 1866908655486500864
author Di Meglio, Matthew
Heunen, Chris
Lemay, Jean-Simon Pacaud
Perrone, Paolo
Stein, Dario
author_facet Di Meglio, Matthew
Heunen, Chris
Lemay, Jean-Simon Pacaud
Perrone, Paolo
Stein, Dario
contents Several categories look like categories of relations, but do not fit the established theory of relations in regular categories. They include the category of surjective multivalued functions, the category of injective partial functions, the category of finite probability spaces and stochastic matrices, and the category of Hilbert spaces and linear contractions. To explain these anomalous examples, we develop a parallel theory of relations in epi-regular independence categories. Just as regular categories correspond to tabular allegories, epi-regular independence categories correspond to dilatory dagger categories. The equivalence maps epi-regular independence categories to their associated dagger category of relations, and dilatory dagger categories to their wide subcategory of coisometries.
format Preprint
id arxiv_https___arxiv_org_abs_2508_01146
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dagger categories of relations: The equivalence of dilatory dagger categories and epi-regular independence categories
Di Meglio, Matthew
Heunen, Chris
Lemay, Jean-Simon Pacaud
Perrone, Paolo
Stein, Dario
Category Theory
18E08, 18M40, 60A05, 46M15, 18B10
Several categories look like categories of relations, but do not fit the established theory of relations in regular categories. They include the category of surjective multivalued functions, the category of injective partial functions, the category of finite probability spaces and stochastic matrices, and the category of Hilbert spaces and linear contractions. To explain these anomalous examples, we develop a parallel theory of relations in epi-regular independence categories. Just as regular categories correspond to tabular allegories, epi-regular independence categories correspond to dilatory dagger categories. The equivalence maps epi-regular independence categories to their associated dagger category of relations, and dilatory dagger categories to their wide subcategory of coisometries.
title Dagger categories of relations: The equivalence of dilatory dagger categories and epi-regular independence categories
topic Category Theory
18E08, 18M40, 60A05, 46M15, 18B10
url https://arxiv.org/abs/2508.01146