English

A Connes-amenable, dual Banach algebra need not have a normal, virtual diagonal

Functional Analysis 2007-05-23 v3 Operator Algebras

Abstract

Let GG be a locally compact group, and let WAP(G)WAP(G) denote the space of weakly almost periodic functions on GG. We show that, if GG is a [SIN][SIN]-group, but not compact, then the dual Banach algebra WAP(G)WAP(G)^\ast does not have a normal, virtual diagonal. Consequently, whenever GG is an amenable, non-compact [SIN][SIN]-group, WAP(G)WAP(G)^\ast is an example of a Connes-amenable, dual Banach algebra without a normal,virtual diagonal.

Keywords

Cite

@article{arxiv.math/0310151,
  title  = {A Connes-amenable, dual Banach algebra need not have a normal, virtual diagonal},
  author = {Volker Runde},
  journal= {arXiv preprint arXiv:math/0310151},
  year   = {2007}
}

Comments

16 pages; some more, minor revisions

R2 v1 2026-07-22T16:58:31.479Z