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Main Authors: Antoine, Ramon, Ara, Pere, Bosa, Joan, Perera, Francesc, Vilalta, Eduard
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.00507
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author Antoine, Ramon
Ara, Pere
Bosa, Joan
Perera, Francesc
Vilalta, Eduard
author_facet Antoine, Ramon
Ara, Pere
Bosa, Joan
Perera, Francesc
Vilalta, Eduard
contents In this paper we explore which part of the ideal lattice of a general ring is parametrized by its Cuntz semigroup $\mathrm{S}(R)$ and its ambient semigroup $Λ(R)$. We identify these classes of ideals as the quasipure ideals (a generalization of pure ideals) in the case of $\mathrm{S}(R)$, and what we term decomposable ideals in the case of $Λ(R)$. For an ($s$-)unital ring $R$, the latter class exhausts all ideals of the ring. We prove that these constructions behave well with respect to quotients. In order to study the passage to inductive limits, we introduce the classes of dense and left normal rings. We show that $\mathrm{S}(R)$ is an abstract Cu-semigroup whenever $R$ is left normal and, for such rings, the assignment $R\mapsto \mathrm{S}(R)$ is continuous. We prove a parallel result for $Λ(R)$ whenever $R$ is a dense ring.
format Preprint
id arxiv_https___arxiv_org_abs_2411_00507
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ideals, quotients, and continuity of the Cuntz semigroup for rings
Antoine, Ramon
Ara, Pere
Bosa, Joan
Perera, Francesc
Vilalta, Eduard
Rings and Algebras
16D25, 06F05, 16D10, 16B99, 46L05
In this paper we explore which part of the ideal lattice of a general ring is parametrized by its Cuntz semigroup $\mathrm{S}(R)$ and its ambient semigroup $Λ(R)$. We identify these classes of ideals as the quasipure ideals (a generalization of pure ideals) in the case of $\mathrm{S}(R)$, and what we term decomposable ideals in the case of $Λ(R)$. For an ($s$-)unital ring $R$, the latter class exhausts all ideals of the ring. We prove that these constructions behave well with respect to quotients. In order to study the passage to inductive limits, we introduce the classes of dense and left normal rings. We show that $\mathrm{S}(R)$ is an abstract Cu-semigroup whenever $R$ is left normal and, for such rings, the assignment $R\mapsto \mathrm{S}(R)$ is continuous. We prove a parallel result for $Λ(R)$ whenever $R$ is a dense ring.
title Ideals, quotients, and continuity of the Cuntz semigroup for rings
topic Rings and Algebras
16D25, 06F05, 16D10, 16B99, 46L05
url https://arxiv.org/abs/2411.00507