Free Lamplighter Groups and a Question of Atiyah
arXiv:1005.2347 · doi:10.1353/ajm.2013.0029
Abstract
We compute the von Neumann dimensions of the kernels of adjacency operators on free lamplighter groups and show that they are irrational, thus providing an elementary constructive answer to a question of Atiyah.
AMSLaTeX, 10 pages, to appear in Amer J Math