A nonseparable amenable operator algebra which is not isomorphic to a {$C^*$}-algebra

Choi, Yemon and Farah, Ilijas and Ozawa, Narutaka (2014) A nonseparable amenable operator algebra which is not isomorphic to a {$C^*$}-algebra. Forum of Mathematics, Sigma, 2: e2. ISSN 2050-5094

[thumbnail of S2050509413000066a]
PDF (S2050509413000066a)
S2050509413000066a.pdf - Published Version
Available under License Creative Commons Attribution.

Download (378kB)


It has been a long-standing question whether every amenable operator algebra is isomorphic to a (necessarily nuclear) C*-algebra. In this note, we give a nonseparable counterexample. Finding out whether a separable counterexample exists remains an open problem. We also initiate a general study of unitarizability of representations of amenable groups in C*-algebras and show that our method cannot produce a separable counterexample.

Item Type:
Journal Article
Journal or Publication Title:
Forum of Mathematics, Sigma
Additional Information:
© The Author(s) 2014 The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution licence <http://creativecommons.org/licenses/by/3.0/>. http://journals.cambridge.org/action/displayJournal?jid=FMS The final, definitive version of this article has been published in the Journal, Forum of Mathematics, Sigma, 2, e2 2014, © 2014 Cambridge University Press.
ID Code:
Deposited By:
Deposited On:
22 Apr 2014 08:55
Last Modified:
15 Jul 2024 14:36