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arXiv · 2605.30147

Principal groupoid models for stable UCT Kirchberg algebras

Samuel Evington·Philipp Sibbel
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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 $\mathcal{O}_\infty$.

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Samuel Evington, Philipp Sibbel. 2026-05-28. Principal groupoid models for stable UCT Kirchberg algebras. https://arxiv.org/abs/2605.30147

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