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arXiv · 2310.12908

The von Neumann inequality for $3\times3$ matrices in the unit Euclidean ball

Dariusz Piekarz
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Abstract

It is shown that the constant $c_{d,3}$ in von Neumann's inequality for d-tuples of commutative and row contractive $3\times3$ matrices, as proved by Hartz, Richter, and Shalit in [2], is independent of the size of the d-tuple. A numerical estimation of the constant is provided.

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Dariusz Piekarz. 2023-10-19. The von Neumann inequality for $3\times3$ matrices in the unit Euclidean ball. https://doi.org/10.1007/s11856-025-2740-3

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