{ "id": "1703.00882", "version": "v1", "published": "2017-03-02T18:17:22.000Z", "updated": "2017-03-02T18:17:22.000Z", "title": "Extending representations of Banach algebras to their biduals", "authors": [ "Eusebio Gardella", "Hannes Thiel" ], "comment": "16 pages", "categories": [ "math.FA", "math.OA" ], "abstract": "We show that a representation of a Banach algebra $A$ on a Banach space $X$ can be extended to a canonical representation of $A^{**}$ on $X$ if and only if certain orbit maps $A\\to X$ are weakly compact. We apply this to study when the essential space of a representation is complemented. This provides a tool to disregard the difference between degenerate and nondegenerate representations on Banach spaces. As an application we show that a C*-algebra $A$ has an isometric representation on an $L^p$-space, for $p\\in[1,\\infty)\\setminus\\{2\\}$, if and only if $A$ is commutative.", "revisions": [ { "version": "v1", "updated": "2017-03-02T18:17:22.000Z" } ], "analyses": { "subjects": [ "47L10", "43A65", "46E30" ], "keywords": [ "banach algebra", "extending representations", "banach space", "nondegenerate representations", "essential space" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }