English

Operator amenability of the Fourier algebra in the cb-multiplier norm

Functional Analysis 2007-10-12 v3 Operator Algebras

Abstract

Let GG be a locally compact group, and let A\cb(G)A_\cb(G) denote the closure of A(G)A(G), the Fourier algebra of GG, in the space of completely bounded multipliers of A(G)A(G). If GG is a weakly amenable, discrete group such that \cstar(G)\cstar(G) is residually finite-dimensional, we show that A\cb(G)A_\cb(G) is operator amenable. In particular, A\cb(F2)A_\cb(F_2) is operator amenable even though F2F_2, the free group in two generators, is not an amenable group. Moreover, we show that, if GG is a discrete group such that A\cb(G)A_\cb(G) is operator amenable, a closed ideal of A(G)A(G) is weakly completely complemented in A(G)A(G) if and only if it has an approximate identity bounded in the cb-multiplier norm.

Keywords

Cite

@article{arxiv.math/0501092,
  title  = {Operator amenability of the Fourier algebra in the cb-multiplier norm},
  author = {Brian E. Forrest and Volker Runde and Nico Spronk},
  journal= {arXiv preprint arXiv:math/0501092},
  year   = {2007}
}

Comments

LaTeX2e; 18 pages; cleaned up a bit