Reciprocal Cuntz--Krieger algebras

Fuente: arXiv
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Main Authors: Matsumoto, Kengo, Sogabe, Taro
Format: Preprint
Published: 2025
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author Matsumoto, Kengo
Sogabe, Taro
author_facet Matsumoto, Kengo
Sogabe, Taro
contents Reciprocality in Kirchberg algebras is a duality between strong extension groups and K-theory groups. We describe a construction of the reciprocal dual algebra $\widehat{\mathcal{A}}$ for a Kirchberg algebra $\mathcal{A}$ with finitely generated K-groups via K-theoretic duality for extensions. In particular, we may concretely realize the reciprocal algebra $\widehat{\mathcal{O}}_A$ for simple Cuntz--Krieger algebras $\mathcal{O}_A$. As a result, the algebra $\widehat{\mathcal{O}}_A$ is realized as a unital simple purely infinite universal $C^*$-algebra generated by a family of partial isometries subject to certain operator relations. We will also study gauge actions on the reciprocal algebra $\widehat{\mathcal{O}}_A$ and prove that there exists an isomorphism between the fundamental groups $π_1({\operatorname{Aut}}({\mathcal{O}}_A))$ and $π_1({\operatorname{Aut}}(\widehat{\mathcal{O}}_A))$ preserving their gauge actions.
format Preprint
id arxiv_https___arxiv_org_abs_2502_18126
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reciprocal Cuntz--Krieger algebras
Matsumoto, Kengo
Sogabe, Taro
Operator Algebras
Reciprocality in Kirchberg algebras is a duality between strong extension groups and K-theory groups. We describe a construction of the reciprocal dual algebra $\widehat{\mathcal{A}}$ for a Kirchberg algebra $\mathcal{A}$ with finitely generated K-groups via K-theoretic duality for extensions. In particular, we may concretely realize the reciprocal algebra $\widehat{\mathcal{O}}_A$ for simple Cuntz--Krieger algebras $\mathcal{O}_A$. As a result, the algebra $\widehat{\mathcal{O}}_A$ is realized as a unital simple purely infinite universal $C^*$-algebra generated by a family of partial isometries subject to certain operator relations. We will also study gauge actions on the reciprocal algebra $\widehat{\mathcal{O}}_A$ and prove that there exists an isomorphism between the fundamental groups $π_1({\operatorname{Aut}}({\mathcal{O}}_A))$ and $π_1({\operatorname{Aut}}(\widehat{\mathcal{O}}_A))$ preserving their gauge actions.
title Reciprocal Cuntz--Krieger algebras
topic Operator Algebras
url https://arxiv.org/abs/2502.18126