Skip to content
Preprint

Ranks of operators and pureness of C*-algebras

Oct 2026 · 0 citations · 23 references
Mathematics

Abstract

For simple, nonelementary C*-algebras, we show uniform density of functions realized as ranks of operators. It follows that strict comparison by traces forces almost divisibility, and hence pureness. As an application, we show that strict comparison implies $\mathcal{Z}$-stability for separable, simple, nonelementary C*-algebras with locally finite nuclear dimension. In particular, the Toms--Winter conjecture holds for approximately subhomogeneous C*-algebras. More generally, we obtain uniform density of ranks for C*-algebras with the Global Glimm Property. Consequently, an exact C*-algebra is pure if and only if it has strict comparison together with the Global Glimm Property.

View source

Similar papers

Preprint Oct 2026

Regular simple nuclear C*-algebras

We prove Z-stability for all simple, separable, pure, nuclear C*-algebras. Combining this with very recent work of Thiel completes the proof of the Toms-Winter conjecture. We do this through the framework of II_1 factorial tracially complete C*-algebras. We characterise regularity for these algebras in various terms. I...

Samuel Evington, Shan-Shan Hua, Christopher Schafhauser et al. · 0 citations
Preprint Oct 2026

C*-algebras of Essentially Tracially Rank One

We introduce the notion of essential tracial rank at most one for simple $C^*$-algebras. We show that separable simple $C^*$-algebras with essential tracial rank at most one have several regularity properties, including stable rank one, strict comparison, and tracial approximate divisibility. A finite amenable simple $...

Hua-Xin Lin · 0 citations
Preprint Aug 2026

Irreducibility and weak spectral gap in free product von Neumann algebras

Consider a free product $(M,\varphi)= (M_1,\varphi_1)* (M_2,\varphi_2)$ of non-trivial von Neumann algebras. Using amalgamated free product techniques, we establish irreducibility and weak spectral gap results for free product subalgebras and the centralizer subalgebra of the free product state. In particular, it is sh...

Aldo Garcia Guinto, Fehmi Ekin Giritlioglu, R. RahulKumar et al. · 0 citations
Preprint Sep 2026

A characterization of simplicity of reduced groupoid C*-algebras

We show that, for a second-countable locally compact Hausdorff \'etale minimal groupoid with compact unit space, simplicity of the reduced groupoid C*-algebra implies the existence of a comeager set of unit points with C*-simple isotropy group. Combining this result with work of Christensen and Neshveyev on exotic comp...

Paolo Boldrini · 0 citations
Preprint Sep 2026

Classifiable C*-algebras have quantum symmetries

We show that every classifiable simple C*-algebra, in particular the Jiang-Su algebra, admits outer actions of several discrete quantum groups, such as finite quantum groups and duals of certain free compact quantum groups. As a consequence of the construction, we provide new examples of hyperfinite subfactors with the...

Kan Kitamura · 0 citations
Preprint Aug 2026

Property (SP) and Inclusions of C*-algebras

As a generalization of Gabe and Neagu's inclusions of real rank zero, we introduce a notion of Property (SP) for inclusions of C*-algebras. We begin the systematic study of SP-inclusions, establishing a topological description in the commutative setting and permanence under many constructions. We also extend known resu...

A. Gow, Roberto Hernández Palomares · 1 citation

We use cookies to run the site and, with your consent, for analytics and to show ads. See our Cookie Policy.