{ "id": "0708.1657", "version": "v2", "published": "2007-08-13T07:25:54.000Z", "updated": "2008-04-30T16:15:45.000Z", "title": "Some inequalities for $(α, β)$-normal operators in Hilbert spaces", "authors": [ "Sever S. Dragomir", "Mohammad Sal Moslehian" ], "comment": "11 pages", "categories": [ "math.FA", "math.OA" ], "abstract": "An operator $T$ acting on a Hilbert space is called $(\\alpha ,\\beta)$-normal ($0\\leq \\alpha \\leq 1\\leq \\beta $) if \\begin{equation*} \\alpha ^{2}T^{\\ast }T\\leq TT^{\\ast}\\leq \\beta ^{2}T^{\\ast}T. \\end{equation*} In this paper we establish various inequalities between the operator norm and its numerical radius of $(\\alpha ,\\beta)$-normal operators in Hilbert spaces. For this purpose, we employ some classical inequalities for vectors in inner product spaces.", "revisions": [ { "version": "v2", "updated": "2008-04-30T16:15:45.000Z" } ], "analyses": { "subjects": [ "47A12" ], "keywords": [ "hilbert space", "normal operators", "inner product spaces", "operator norm", "classical inequalities" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0708.1657D" } } }