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arXiv · 2009.11597

Norm derivatives and geometry of bilinear operators

Divya Khurana·Debmalya Sain
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Abstract

We study the norm derivatives in the context of Birkhoff-James orthogonality in real Banach spaces. As an application of this, we obtain a complete characterization of the left-symmetric points and the right-symmetric points in a real Banach space in terms of the norm derivatives. We obtain a complete characterization of strong Birkhoff-James orthogonality in $\ell_1^n$ and $\ell_\infty^n$ spaces. We also obtain a complete characterization of the orthogonality relation defined by the norm derivatives in terms of some newly introduced variation of Birkhoff-James orthogonality. We further study Birkhoff-James orthogonality, approximate Birkhoff-James orthogonality, smoothness and norm attainment of bounded bilinear operators between Banach spaces.

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Divya Khurana, Debmalya Sain. 2020-09-24. Norm derivatives and geometry of bilinear operators. https://arxiv.org/abs/2009.11597

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