Amenability constants for semilattice algebras
Functional Analysis
2011-11-10 v2
Abstract
For any finite unital commutative idempotent semigroup S, a unital semilattice, we show how to compute the amenability constant of its semigroup algebra l^1(S), which is always of the form 4n+1. We then show that these give lower bounds to amenability constants of certain Banach algebras graded over semilattices. We show that there is no commutative semilattice with amenability constant between 5 and 9.
Keywords
Cite
@article{arxiv.0705.4279,
title = {Amenability constants for semilattice algebras},
author = {Mahya Ghandehari and Hamed Hatami and Nico Spronk},
journal= {arXiv preprint arXiv:0705.4279},
year = {2011}
}