English

The undecidability of having the QWEP

Operator Algebras 2023-08-29 v2 Logic

Abstract

We show that neither the class of C*-algebras with Kirchberg's QWEP property nor the class of W*-probability spaces with the QWEP property are effectively axiomatizable (in the appropriate languages). The latter result follows from a more general result, namely that the hyperfinite III1_1 factor does not have a computable universal theory in the language of W*-probability spaces. We also prove that the Powers' factors Rλ\mathcal{R}_\lambda, for 0<λ<10<\lambda<1, when equipped with their canonical Powers' states, do not have computable universal theory.

Keywords

Cite

@article{arxiv.2205.07102,
  title  = {The undecidability of having the QWEP},
  author = {Jananan Arulseelan and Isaac Goldbring and Bradd Hart},
  journal= {arXiv preprint arXiv:2205.07102},
  year   = {2023}
}

Comments

14 pages; a minor mistake in Theorem 2.1 has been fixed, leading to a stronger conclusion. Final version, to appear in Journal of Operator Theory