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arXiv · 2302.05389

On Abstract Spectral Constants

Felix L. Schwenninger·Jens de Vries
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Abstract

We prove bounds for a class of unital homomorphisms arising in the study of spectral sets, by involving extremal functions and vectors. These are used to recover three celebrated results on spectral constants by Crouzeix--Palencia, Okubo--Ando and von Neumann in a unified way and to refine a recent result by Crouzeix--Greenbaum.

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Felix L. Schwenninger, Jens de Vries. 2023-02-10. On Abstract Spectral Constants. https://arxiv.org/abs/2302.05389

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