English

Nowhere scattered C*-algebras

Operator Algebras 2022-10-21 v2

Abstract

We say that a C*-algebra is nowhere scattered if none of its quotients contains a minimal open projection. We characterize this property in various ways, by topological properties of the spectrum, by divisibility properties in the Cuntz semigroup, by the existence of Haar unitaries for states, and by the absence of nonzero ideal-quotients that are elementary, scattered or type I. Under the additional assumption of real rank zero or stable rank one, we show that nowhere scatteredness implies even stronger divisibility properties of the Cuntz semigroup.

Keywords

Cite

@article{arxiv.2112.09877,
  title  = {Nowhere scattered C*-algebras},
  author = {Hannes Thiel and Eduard Vilalta},
  journal= {arXiv preprint arXiv:2112.09877},
  year   = {2022}
}

Comments

26 pages; minor revision; changed terminology "minimal projection" to "minimal open projection" to avoid confusion; to appear in J. Noncommut. Geom

R2 v1 2026-06-24T08:22:56.578Z