English

AF $C^*$-algebras from non AF groupoids

Operator Algebras 2022-07-06 v4

Abstract

We construct ample groupoids from certain categories of paths, and prove that their CC^*-algebras coincide with the continued fraction AF algebras of Effros and Shen. The proof relies on recent classification results for simple nuclear CC^*-algebras. The groupoids are not principal. This provides examples of Cartan subalgebras in the continued fraction AF algebras that are isomorphic, but not conjugate, to the standard diagonal subalgebras.

Keywords

Cite

@article{arxiv.2106.14032,
  title  = {AF $C^*$-algebras from non AF groupoids},
  author = {Ian Mitscher and Jack Spielberg},
  journal= {arXiv preprint arXiv:2106.14032},
  year   = {2022}
}

Comments

version 4: final version, to appear in Transactions AMS; minor errors corrected

R2 v1 2026-06-24T03:37:38.258Z