4 papers
K-theory of C*-algebras arising from commuting Hilbert bimodules and invariant ideals
Astrid an Huef, Abraham C. S. Ng, Aidan Sims
We study the K-theory of the Cuntz-Nica-Pimsner C*-algebra of a rank-two product system that is an extension determined by an invariant ideal of the coefficient algebra. We use a c…
Nuclear dimension of extensions of commutative C*-algebras by Kirchberg algebras
Samuel Evington, Abraham C. S. Ng, Aidan Sims +1
We compute the nuclear dimension of extensions of C*-algebras involving commutative unital quotients and stable Kirchberg ideals. We identify the finite directed graphs whose C*-al…
A twist over a minimal étale groupoid that is topologically nontrivial over the interior of the isotropy
Becky Armstrong, Abraham C. S. Ng, Aidan Sims +1
We present an example of a twist over a minimal Hausdorff étale groupoid such that the restriction of the twist to the interior of the isotropy is not topologically trivial; that i…
Stably finite extensions of rank-two graph C*-algebras
Astrid an Huef, Abraham C. S. Ng, Aidan Sims
We study stable finiteness of extensions of 2-graph C*-algebras determined by saturated hereditary sets of vertices. We use two iterations of the Pimsner-Voiculescu sequence to cal…