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arXiv · 1903.06858

Orthogonality and Numerical radius inequalities of operator matrices

Arpita Mal·Kallol Paul·Jeet Sen
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Abstract

We completely characterize Birkhoff-James orthogonality with respect to numerical radius norm in the space of bounded linear operators on a complex Hilbert space. As applications of the results obtained, we estimate lower bounds of numerical radius for $n\times n$ operator matrices, which improve on and generalize existing lower bounds. We also obtain a better lower bound of numerical radius for an upper triangular operator matrix.

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Arpita Mal, Kallol Paul, Jeet Sen. 2019-03-16. Orthogonality and Numerical radius inequalities of operator matrices. https://doi.org/10.1007/s00605-021-01638-1

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