RANKS OF SOFT OPERATORS IN NOWHERE SCATTERED $\mathrm {C}^*$-ALGEBRAS

Abstract We show that for $\mathrm {C}^*$ -algebras with the global Glimm property, the rank of every operator can be realized as the rank of a soft operator, that is, an element whose hereditary sub- $\mathrm {C}^*$ -algebra has no nonzero, unital quotients. This implies that the radius of comparison of such a $\mathrm {C}^*$ -algebra is determined by the soft part of its Cuntz semigroup. Under a mild additional assumption, we show that every Cuntz class dominates a (unique) largest soft Cuntz class. This defines a retract from the Cuntz semigroup onto its soft part, and it follows that the covering dimensions of these semigroups differ by at most $1$ .

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Publication Details

Journal
Journal of the Institute of Mathematics of Jussieu
Published
2024-12-20
DOI
https://doi.org/10.1017/s1474748024000318
Citations
2
Primary Topic
Advanced Topics in Algebra
Type
article
Field-Weighted Citation Impact
2.54

Funders

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article

RANKS OF SOFT OPERATORS IN NOWHERE SCATTERED $\mathrm {C}^*$-ALGEBRAS

Hannes Thiel, M. Ali Asadi-Vasfi, Eduard Vilalta
2 citations
Journal of the Institute of Mathematics of Jussieu
Advanced Topics in Algebra
2.54
article

RANKS OF SOFT OPERATORS IN NOWHERE SCATTERED $\mathrm {C}^*$-ALGEBRAS

Hannes Thiel, M. Ali Asadi-Vasfi, Eduard Vilalta
article en
2 citations

Abstract

Abstract We show that for $\mathrm {C}^*$ -algebras with the global Glimm property, the rank of every operator can be realized as the rank of a soft operator, that is, an element whose hereditary sub- $\mathrm {C}^*$ -algebra has no nonzero, unital quotients. This implies that the radius of comparison of such a $\mathrm {C}^*$ -algebra is determined by the soft part of its Cuntz semigroup. Under a mild additional assumption, we show that every Cuntz class dominates a (unique) largest soft Cuntz class. This defines a retract from the Cuntz semigroup onto its soft part, and it follows that the covering dimensions of these semigroups differ by at most $1$ .

Journal of the Institute of Mathematics of JussieuVol. 24(2)
University of Toronto (CA), Chalmers University of Technology (SE), University of Gothenburg (SE), Fields Institute for Research in Mathematical Sciences (CA)
Deutsche Forschungsgemeinschaft, Generalitat de Catalunya, Knut och Alice Wallenbergs Stiftelse, Akademie Věd České Republiky, Westfälische Wilhelms-Universität Münster, Division of Mathematical Sciences
Openalex Percentile: Top 9%
Advanced Topics in Algebra
2.54
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