Constructing strictly sign regular matrices of all sizes and sign patterns

Fuente: arXiv
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Autori principali: Choudhury, Projesh Nath, Yadav, Shivangi
Natura: Preprint
Pubblicazione: 2024
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author Choudhury, Projesh Nath
Yadav, Shivangi
author_facet Choudhury, Projesh Nath
Yadav, Shivangi
contents The class of strictly sign regular (SSR) matrices has been extensively studied by many authors over the past century, notably by Schoenberg, Motzkin, Gantmacher, and Krein. A classical result of Gantmacher-Krein assures the existence of SSR matrices for any dimension and sign pattern. In this article, we provide an algorithm to explicitly construct an SSR matrix of any given size and sign pattern. (We also provide in an Appendix, a Python code implementing our algorithm.) To develop this algorithm, we show that one can extend an SSR matrix by adding an extra row (column) to its border, resulting in a higher order SSR matrix. Furthermore, we show how inserting a suitable new row/column between any two successive rows/columns of an SSR matrix results in a matrix that remains SSR. We also establish analogous results for strictly sign regular $m \times n$ matrices of order $p$ for any $p \in [1, \min\{m,n\}]$.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14287
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Constructing strictly sign regular matrices of all sizes and sign patterns
Choudhury, Projesh Nath
Yadav, Shivangi
Rings and Algebras
15B48, 15A83, 15A15, 15-04
The class of strictly sign regular (SSR) matrices has been extensively studied by many authors over the past century, notably by Schoenberg, Motzkin, Gantmacher, and Krein. A classical result of Gantmacher-Krein assures the existence of SSR matrices for any dimension and sign pattern. In this article, we provide an algorithm to explicitly construct an SSR matrix of any given size and sign pattern. (We also provide in an Appendix, a Python code implementing our algorithm.) To develop this algorithm, we show that one can extend an SSR matrix by adding an extra row (column) to its border, resulting in a higher order SSR matrix. Furthermore, we show how inserting a suitable new row/column between any two successive rows/columns of an SSR matrix results in a matrix that remains SSR. We also establish analogous results for strictly sign regular $m \times n$ matrices of order $p$ for any $p \in [1, \min\{m,n\}]$.
title Constructing strictly sign regular matrices of all sizes and sign patterns
topic Rings and Algebras
15B48, 15A83, 15A15, 15-04
url https://arxiv.org/abs/2411.14287