{ "id": "2102.01953", "version": "v1", "published": "2021-02-03T09:04:42.000Z", "updated": "2021-02-03T09:04:42.000Z", "title": "Furtherance of Numerical radius inequalities of Hilbert space operators", "authors": [ "Pintu Bhunia", "Kallol Paul" ], "comment": "9 pages", "categories": [ "math.FA" ], "abstract": "If $A,B$ are bounded linear operators on a complex Hilbert space, then % $w(A) \\leq \\frac{1}{2}\\left( \\|A\\|+\\sqrt{r\\left(|A||A^*|\\right)}\\right)$ and $w(AB \\pm BA)\\leq 2\\sqrt{2}\\|B\\|\\sqrt{ w^2(A)-\\frac{c^2(\\Re (A))+c^2(\\Im (A))}{2} },$ \\begin{eqnarray*} w(A) &\\leq& \\frac{1}{2}\\left( \\|A\\|+\\sqrt{r\\left(|A||A^*|\\right)}\\right),\\\\ w(AB \\pm BA)&\\leq& 2\\sqrt{2}\\|B\\|\\sqrt{ w^2(A)-\\frac{c^2(\\Re (A))+c^2(\\Im (A))}{2} }, \\end{eqnarray*} where $w(.),\\|.\\|,c(.)$ and $r(.)$ are the numerical radius, the operator norm, the Crawford number and the spectral radius respectively, and $\\Re (A)$, $\\Im (A)$ are the real part, the imaginary part of $A$ respectively. The inequalities obtained here generalize and improve on the existing well known inequalities.", "revisions": [ { "version": "v1", "updated": "2021-02-03T09:04:42.000Z" } ], "analyses": { "subjects": [ "47A12", "47A30" ], "keywords": [ "hilbert space operators", "numerical radius inequalities", "furtherance", "complex hilbert space", "real part" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }