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Main Authors: Fornasiere, Damiano, Moraschini, Tommaso
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.04215
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author Fornasiere, Damiano
Moraschini, Tommaso
author_facet Fornasiere, Damiano
Moraschini, Tommaso
contents A poset is Esakia representable when it is isomorphic to the prime spectrum of a Heyting algebra. Notably, every Esakia representable poset is also the spectrum of a commutative ring with unit. The problem of describing the Esakia representable posets was raised in 1985 and remains open to this day. We recall that a forest is a disjoint union of trees and that a root system is the order dual of a forest. It is shown that a root system is Esakia representable if and only if it satisfies a simple order theoretic condition, known as "having enough gaps", and each of its nonempty chains has an infimum. This strengthens Lewis's characterisation of the root systems which are spectra of commutative rings with unit. While a similar characterisation of arbitrary Esakia representable forests seems currently out of reach, we show that a well-ordered forest is Esakia representable if and only if it has enough gaps and each of its nonempty chains has a supremum.
format Preprint
id arxiv_https___arxiv_org_abs_2410_04215
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Trees and spectra of Heyting algebras
Fornasiere, Damiano
Moraschini, Tommaso
Logic
Rings and Algebras
A poset is Esakia representable when it is isomorphic to the prime spectrum of a Heyting algebra. Notably, every Esakia representable poset is also the spectrum of a commutative ring with unit. The problem of describing the Esakia representable posets was raised in 1985 and remains open to this day. We recall that a forest is a disjoint union of trees and that a root system is the order dual of a forest. It is shown that a root system is Esakia representable if and only if it satisfies a simple order theoretic condition, known as "having enough gaps", and each of its nonempty chains has an infimum. This strengthens Lewis's characterisation of the root systems which are spectra of commutative rings with unit. While a similar characterisation of arbitrary Esakia representable forests seems currently out of reach, we show that a well-ordered forest is Esakia representable if and only if it has enough gaps and each of its nonempty chains has a supremum.
title Trees and spectra of Heyting algebras
topic Logic
Rings and Algebras
url https://arxiv.org/abs/2410.04215