{"title":"Sign patterns of semimonotone matrices","authors":"Aritra Narayan Hisabia , Manideepa Saha","doi":"10.1016/j.laa.2025.06.019","DOIUrl":null,"url":null,"abstract":"<div><div>A real matrix <em>A</em> is called a (strictly) semimonotone matrix if for any nonnegative nonzero vector <em>x</em>, there exists an index <em>k</em> such that <span><math><msub><mrow><mi>x</mi></mrow><mrow><mi>k</mi></mrow></msub></math></span> is positive and <span><math><msub><mrow><mo>(</mo><mi>A</mi><mi>x</mi><mo>)</mo></mrow><mrow><mi>k</mi></mrow></msub></math></span> is (positive) nonnegative. A sign pattern matrix (or sign pattern) <em>S</em> is a matrix with entries from the set <span><math><mo>{</mo><mo>+</mo><mo>,</mo><mo>−</mo><mo>,</mo><mn>0</mn><mo>}</mo></math></span>. The paper aims to study the sign pattern <em>S</em> that allows (strictly) semimonotonicity (if there exists a (strictly) semimonotone matrix with sign pattern <em>S</em>) or requires (strictly) semimonotonicity (every matrix of sign pattern <em>S</em> is (strictly) semimonotone), and to discuss a few algebraic properties of semimonotone matrices. In particular, we provide characterizations of sign pattern matrices that allow strictly semimonotonicity. We also present a necessary and sufficient condition for a sign pattern to require semimonotonicity and strictly semimonotonicity. Furthermore, we show the existence of a basis of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi><mo>×</mo><mi>n</mi></mrow></msup></math></span>, consisting of semimonotone and strictly semimonotone matrices. At last, we characterize rank one semimonotone and strictly semimonotone matrices.</div></div>","PeriodicalId":18043,"journal":{"name":"Linear Algebra and its Applications","volume":"724 ","pages":"Pages 206-217"},"PeriodicalIF":1.1000,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Linear Algebra and its Applications","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S002437952500271X","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
A real matrix A is called a (strictly) semimonotone matrix if for any nonnegative nonzero vector x, there exists an index k such that is positive and is (positive) nonnegative. A sign pattern matrix (or sign pattern) S is a matrix with entries from the set . The paper aims to study the sign pattern S that allows (strictly) semimonotonicity (if there exists a (strictly) semimonotone matrix with sign pattern S) or requires (strictly) semimonotonicity (every matrix of sign pattern S is (strictly) semimonotone), and to discuss a few algebraic properties of semimonotone matrices. In particular, we provide characterizations of sign pattern matrices that allow strictly semimonotonicity. We also present a necessary and sufficient condition for a sign pattern to require semimonotonicity and strictly semimonotonicity. Furthermore, we show the existence of a basis of , consisting of semimonotone and strictly semimonotone matrices. At last, we characterize rank one semimonotone and strictly semimonotone matrices.
期刊介绍:
Linear Algebra and its Applications publishes articles that contribute new information or new insights to matrix theory and finite dimensional linear algebra in their algebraic, arithmetic, combinatorial, geometric, or numerical aspects. It also publishes articles that give significant applications of matrix theory or linear algebra to other branches of mathematics and to other sciences. Articles that provide new information or perspectives on the historical development of matrix theory and linear algebra are also welcome. Expository articles which can serve as an introduction to a subject for workers in related areas and which bring one to the frontiers of research are encouraged. Reviews of books are published occasionally as are conference reports that provide an historical record of major meetings on matrix theory and linear algebra.