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APPROXIMATION OF BLOCK NUMERICAL RANGE FOR HAMILTONIAN OPERATOR MATRIX

ABSTRACT
The aim of this paper is to derive approximations for the block numerical range of unbounded block operator matrices that are block dominant. To illustrate our approach, we calculate the quartic numerical range of a concrete Hamiltonian operator matrix.
KEYWORDS
PAPER SUBMITTED: 2024-03-23
PAPER REVISED: 2024-06-23
PAPER ACCEPTED: 2024-06-23
PUBLISHED ONLINE: 2025-07-06
DOI REFERENCE: https://doi.org/10.2298/TSCI2503085Y
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2025, VOLUME 29, ISSUE Issue 3, PAGES [2085 - 2093]
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2025 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence