Principal groupoid models for stable UCT Kirchberg algebras

Authors: Samuel Evington, Philipp Sibbel

math.OA2026-05v1license

Abstract

We show that every stable UCT Kirchberg algebra has a principal \'etale groupoid model, and thus contains a C $^*$ -diagonal. Every unital UCT Kirchberg algebra $A$ for which $[1_A]_0$ has infinite order in $K_0(A)$ is also covered by our methods. In particular, we obtain a principal \'etale groupoid model for the Cuntz algebra $\mathcal{O}_\infty$ .

Comments: 16 pages

Cite

@article{arxiv.2605.30147,
  title  = {Principal groupoid models for stable UCT Kirchberg algebras},
  author = {Samuel Evington and Philipp Sibbel},
  journal= {arXiv preprint arXiv:2605.30147},
  year   = {2026}
}

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