{ "id": "1304.6193", "version": "v5", "published": "2013-04-23T07:52:42.000Z", "updated": "2013-08-26T14:30:24.000Z", "title": "Notes on C_0-representations and the Haagerup property", "authors": [ "Paul Jolissaint" ], "comment": "Notes partly of an expository nature; 11 pages; a few typos fixed; final version to appear in the Bulletin of the Belgian Mathematical Society - Simon Stevin", "categories": [ "math.GR" ], "abstract": "For any locally compact group $G$, we show the existence and uniqueness up to quasi-equivalence of a unitary $C_0$-representation $\\pi_0$ of $G$ such that all coefficient functions of $C_0$-representations of $G$ are coefficient functions of $\\pi_0$. The present work, strongly influenced by the work of N. Brown and E. Guentner (which dealt exclusively with discrete groups), leads to new characterizations of the Haagerup property: if $G$ is second countable, then it has that property if and only if the representation $\\pi_0$ induces a *-isomorphism of $C^*(G)$ onto $C^*_{\\pi_0}(G)$. When $G$ is discrete, we also relate the Haagerup property to relative strong mixing properties of the group von Neumann algebra $L(G)$ into finite von Neumann algebras.", "revisions": [ { "version": "v5", "updated": "2013-08-26T14:30:24.000Z" } ], "analyses": { "subjects": [ "22D10", "22D25", "46L10" ], "keywords": [ "haagerup property", "finite von neumann algebras", "group von neumann algebra", "coefficient functions", "representation" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1304.6193J" } } }