English

Ranks of soft operators in nowhere scattered C*-algebras

Operator Algebras 2023-10-03 v1

Abstract

We show that for 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-C*-algebra has no nonzero, unital quotients. This implies that the radius of comparison of such a 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 11.

Keywords

Cite

@article{arxiv.2310.00663,
  title  = {Ranks of soft operators in nowhere scattered C*-algebras},
  author = {M. Ali Asadi-Vasfi and Hannes Thiel and Eduard Vilalta},
  journal= {arXiv preprint arXiv:2310.00663},
  year   = {2023}
}

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33 pages