{ "id": "1804.09207", "version": "v1", "published": "2018-04-24T18:39:45.000Z", "updated": "2018-04-24T18:39:45.000Z", "title": "Finitely $\\mathcal{F}$-amenable actions and Decomposition Complexity of Groups", "authors": [ "Andrew Nicas", "David Rosenthal" ], "categories": [ "math.GT", "math.GR" ], "abstract": "In his work on the Farrell-Jones Conjecture, Arthur Bartels introduced the concept of a \"finitely $\\mathcal{F}$-amenable\" group action, where $\\mathcal{F}$ is a family of subgroups. We show how a finitely $\\mathcal{F}$-amenable action of a finitely generated group $G$ on a compact metric space, where the asymptotic dimensions of the elements of $\\mathcal{F}$ are bounded from above, gives an upper bound for the asymptotic dimension of $G$. We generalize this to families $\\mathcal{F}$ whose elements are contained in a collection, $\\mathfrak{C}$, of metric families that satisfies some basic permanence properties: If $G$ is a finitely generated group and each element of $\\mathcal{F}$ belongs to $\\mathfrak{C}$ and there exists a finitely $\\mathcal{F}$-amenable action of $G$ on a compact metrizable space, then $G$ is in $\\mathfrak{C}$. Examples of such collections of metric families include: metric families with weak finite decomposition complexity, exact metric families, and metric families that coarsely embed into Hilbert space.", "revisions": [ { "version": "v1", "updated": "2018-04-24T18:39:45.000Z" } ], "analyses": { "subjects": [ "20F69", "20F65" ], "keywords": [ "amenable action", "weak finite decomposition complexity", "finitely generated group", "asymptotic dimension", "compact metric space" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }