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arXiv · 2508.12039

Krein Space Numerical Range of Block Matrices -- a Unified Approach to the Hyperbolic Case

N. Bebiano·R. Lemos·G. Soares
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Abstract

In this paper, we investigate the Krein space numerical range of $2$-by-$2$ block matrices, with diagonal blocks as scalar multiples of the identity. For these matrices, we specifically investigate the cases when the respective boundary generating curves consist of hyperbolas. This provides a unified approach to derive established and new results concerning the numerical range hyperbolic shape.

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N. Bebiano, R. Lemos, G. Soares. 2025-08-16. Krein Space Numerical Range of Block Matrices -- a Unified Approach to the Hyperbolic Case. https://arxiv.org/abs/2508.12039

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