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Autori principali: Kamio, Yuhi, Hora, Ryuya
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2407.17105
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author Kamio, Yuhi
Hora, Ryuya
author_facet Kamio, Yuhi
Hora, Ryuya
contents This paper solves the first of the open problems in topos theory posted by William Lawvere, concerning the existence of a Grothendieck topos that has proper class many quotient topoi. This paper concretely constructs such Grothendieck topoi, including the presheaf topos on the free monoid generated by countably infinitely many elements PSh(M_ω). Utilizing the combinatorics of the classifying topos of the theory of inhabited objects and with the help of a system of pairing functions, the problem is reduced to a theorem of Vopenka, Pultr, and Hedrlin, which states that any set admits a rigid relational structure.
format Preprint
id arxiv_https___arxiv_org_abs_2407_17105
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Solution to Lawvere's first problem: a Grothendieck topos that has proper class many quotient topoi
Kamio, Yuhi
Hora, Ryuya
Category Theory
18F10, 18B25, 03C50
This paper solves the first of the open problems in topos theory posted by William Lawvere, concerning the existence of a Grothendieck topos that has proper class many quotient topoi. This paper concretely constructs such Grothendieck topoi, including the presheaf topos on the free monoid generated by countably infinitely many elements PSh(M_ω). Utilizing the combinatorics of the classifying topos of the theory of inhabited objects and with the help of a system of pairing functions, the problem is reduced to a theorem of Vopenka, Pultr, and Hedrlin, which states that any set admits a rigid relational structure.
title Solution to Lawvere's first problem: a Grothendieck topos that has proper class many quotient topoi
topic Category Theory
18F10, 18B25, 03C50
url https://arxiv.org/abs/2407.17105