English

A note on purely infinite corona algebras and extensions

Operator Algebras 2026-02-25 v1

Abstract

Let A\mathcal{A} be a separable nuclear C*-algebra, and B\mathcal{B} be a nonunital separable simple Z\mathcal{Z}-stable C*-algebra. Continuing the work from Gabe-Lin-Ng, we classify all essential extensions, with large complement, of the form 0BEA0,0 \rightarrow \mathcal{B} \rightarrow \mathcal{E} \rightarrow \mathcal{A} \rightarrow 0, for the following cases: i. C(B)\mathcal{C}(\mathcal{B}) is properly infinite, and the extension is full. ii. C(B)\mathcal{C}(\mathcal{B}) is purely infinite (though not necessarily simple). We also have some more general results.

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Cite

@article{arxiv.2602.20591,
  title  = {A note on purely infinite corona algebras and extensions},
  author = {Ping Wong Ng and Cangyuan Wang},
  journal= {arXiv preprint arXiv:2602.20591},
  year   = {2026}
}

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17 pages