{ "id": "math/0508028", "version": "v2", "published": "2005-08-01T09:21:00.000Z", "updated": "2006-04-22T08:56:12.000Z", "title": "Automatic Continuity of $σ$-Derivations on $C^*$-Algebras", "authors": [ "Madjid Mirzavaziri", "Mohammad Sal Moslehian" ], "comment": "8 pages, some minor corrections, to appear in Proc. Amer. Math. Soc", "journal": "Proc. Amer. Math. Soc. 134 (2006), no. 11, 3319-3327.", "categories": [ "math.FA", "math.OA" ], "abstract": "Let $A$ be a $C^*$-algebra acting on a Hilbert space $H$, $\\sigma:A\\to B(H)$ be a linear mapping and $d:A\\to B(H)$ be a $\\sigma$-derivation. Generalizing the celebrated theorem of Sakai, we prove that if $\\sigma$ is a continuous $*$-mapping then $d$ is automatically continuous. In addition, we show the converse is true in the sense that if $d$ is a continuous $*-\\sigma$-derivation then there exists a continuous linear mapping $\\Sigma:A\\to B(H)$ such that $d$ is $*-\\Sigma$-derivation. The continuity of the so-called $*-(\\sigma,\\tau)$-derivations is also discussed.", "revisions": [ { "version": "v2", "updated": "2006-04-22T08:56:12.000Z" } ], "analyses": { "subjects": [ "46L57", "46L05", "47B47" ], "keywords": [ "derivation", "automatic continuity", "hilbert space", "linear mapping" ], "tags": [ "journal article" ], "publication": { "publisher": "AMS", "journal": "Proc. Amer. Math. Soc." }, "note": { "typesetting": "TeX", "pages": 8, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2005math......8028M" } } }