Upper and lower bounds for the numerical radius with an application to involution operators (Q888099)
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scientific article; zbMATH DE number 6504429
| Language | Label | Description | Also known as |
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| English | Upper and lower bounds for the numerical radius with an application to involution operators |
scientific article; zbMATH DE number 6504429 |
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Upper and lower bounds for the numerical radius with an application to involution operators (English)
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4 November 2015
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Using the numerical radius of \(A^2\), the authors improve the upper bound of the numerical radius of \(A\) which was obtained by the second author [Stud. Math. 158, No. 1, 11--17 (2003; Zbl 1113.15302); Stud. Math. 168, No. 1, 73--80 (2005; Zbl 1072.47004)]. Also, considering the infimum of the numerical range of \(A\), a lower bound for numerical radius of \(A\) is presented which is sharper than the one in [Zbl 1072.47004].
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numerical radius
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operator norm
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inequality
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involution operator
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