In this paper, the boundary generating curves and the numerical range of Kac-Sylvester
matrices up to the order $9 $ are characterized. Based on the obtained results and on …

By definition, reciprocal matrices are tridiagonal n-by-n matrices A with constant main
diagonal and such that ai, i+ 1 ai+ 1, i= 1 for i= 1,..., n− 1. We establish some properties of …

In this paper the boundary generating curves and numerical ranges of centrosymmetric
matrices of orders up to 6 are characterized in terms of the matrices entries. These results …

We consider tridiagonal matrices (a ij) i, j= 1 n with constant main diagonal and such that ai,
i+ 1 ai+ 1, i= 1 for i= 1,…, n− 1. For these matrices, criteria are established under which their …

This paper is devoted to matrices with hyperbolical Krein space numerical range. This shape
characterizes the 2-by-2 case and persists for certain classes of matrices, independently of …

The envelope of a square complex matrix is a closed and bounded subset of the numerical
range which contains the spectrum. We study the envelope of special classes of 3× 3 …

Ilya Spitkovsky 70 | SpringerLink Skip to main content Advertisement SpringerLink Account
Menu Find a journal Publish with us Track your research Search Cart 1.Home 2.Analysis …

The higher-rank numerical range is a convex compact set generalizing the classical
numerical range of a square complex matrix, first appearing in the study of quantum error …

[16] P.-A. Absil, R. Mahony, and B. Andrews. Convergence of the iterates of descent
methods for analytic cost functions. SIAM J. Optim., 16 (2): 531–547, 2005.[17] A. Abu-Omar …

The numerical range of a complex square matrix is the convex hull of a plane real algebraic
curve. Kippenhahn discovered this important statement of matrix theory and outlined its …