On the maximal spread of symmetric Bohemian matrices

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Calkin, Neil J., Corless, Robert M., Gonzalez-Vega, Laureano, Sendra, J. Rafael, Sendra, Juana
Formato: Preprint
Publicado: 2025
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866909854052909056
author Calkin, Neil J.
Corless, Robert M.
Gonzalez-Vega, Laureano
Sendra, J. Rafael
Sendra, Juana
author_facet Calkin, Neil J.
Corless, Robert M.
Gonzalez-Vega, Laureano
Sendra, J. Rafael
Sendra, Juana
contents Let A be a square matrix with real entries. The spread of A is defined as the maximum of the distances among the eigenvalues of A. Let $S_m[a,b]$ denote the set of all $m\times m$ symmetric matrices with entries in the real interval $[a,b]$ and let $S_m\{a,b\}$ be the subset of $S_m[a,b]$ of Bohemian matrices with population from only the extremal elements $\{a,b\}$. S. M. Fallat and J. J. Xing in 2012 proposed the following conjecture: the maximum spread in $S_m[a,b]$ is attained by a rank $2$ matrix in $S_m\{a,b\}$. X. Zhan had proved previously that the conjecture was true for $S_m[-a,a]$ with $a>0$. We will show how to interpret this problem geometrically, via polynomial resultants, in order to be able to treat this conjecture from a computational point of view. This will allow us to prove that this conjecture is true for several formerly open cases.
format Preprint
id arxiv_https___arxiv_org_abs_2510_15919
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the maximal spread of symmetric Bohemian matrices
Calkin, Neil J.
Corless, Robert M.
Gonzalez-Vega, Laureano
Sendra, J. Rafael
Sendra, Juana
Spectral Theory
05C50, 34L15
Let A be a square matrix with real entries. The spread of A is defined as the maximum of the distances among the eigenvalues of A. Let $S_m[a,b]$ denote the set of all $m\times m$ symmetric matrices with entries in the real interval $[a,b]$ and let $S_m\{a,b\}$ be the subset of $S_m[a,b]$ of Bohemian matrices with population from only the extremal elements $\{a,b\}$. S. M. Fallat and J. J. Xing in 2012 proposed the following conjecture: the maximum spread in $S_m[a,b]$ is attained by a rank $2$ matrix in $S_m\{a,b\}$. X. Zhan had proved previously that the conjecture was true for $S_m[-a,a]$ with $a>0$. We will show how to interpret this problem geometrically, via polynomial resultants, in order to be able to treat this conjecture from a computational point of view. This will allow us to prove that this conjecture is true for several formerly open cases.
title On the maximal spread of symmetric Bohemian matrices
topic Spectral Theory
05C50, 34L15
url https://arxiv.org/abs/2510.15919