English

Self-adjoint traces on the Pedersen ideal of $\mathrm{C}^\ast$-algebras

Operator Algebras 2025-03-12 v2

Abstract

In order to circumvent a fundamental issue when studying densely defined traces on C\mathrm{C}^\ast-algebras -- which we refer to as the Trace Question -- we initiate a systematic study of the set TR(A)T_{\mathbb R}(A) of self-adjoint traces on the Pedersen ideal of AA. The set TR(A)T_{\mathbb R}(A) is a topological vector space with a vector lattice structure, which in the unital setting reflects the Choquet simplex structure of the tracial states. We establish a form of Kadison duality for TR(A)T_{\mathbb R}(A) and compute TR(A)T_{\mathbb R}(A) for principal twisted \'etale groupoid C\mathrm{C}^\ast-algebras. We also answer the Trace Question positively for a large class of C\mathrm{C}^\ast-algebras.

Keywords

Cite

@article{arxiv.2409.03587,
  title  = {Self-adjoint traces on the Pedersen ideal of $\mathrm{C}^\ast$-algebras},
  author = {James Gabe and Alistair Miller},
  journal= {arXiv preprint arXiv:2409.03587},
  year   = {2025}
}

Comments

V2: minor changes, to appear in Publ. Mat