{"title":"Eigenvalues and signature of quadratic forms associated with finite topological spaces","authors":"Pedro J. Chocano","doi":"10.1016/j.laa.2025.09.007","DOIUrl":null,"url":null,"abstract":"<div><div>Given any finite topological space <em>X</em> and a field <span><math><mi>K</mi></math></span>, we associate a quadratic space <span><math><mo>(</mo><msub><mrow><mi>Q</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>,</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>)</mo></math></span>, consisting of a vector space <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>X</mi></mrow></msub></math></span> over <span><math><mi>K</mi></math></span> and a quadratic form <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>:</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>×</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>→</mo><mi>K</mi></math></span>, to <em>X</em>. The eigenvalues and signature of <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mi>X</mi></mrow></msub></math></span> are topological invariants of <em>X</em>. We study their relations with <em>X</em>. From this, we obtain restrictions to check whether a finite topological space can be embedded into another one. Additionally, we compute these invariants for minimal finite models of spheres and other families of finite spaces.</div></div>","PeriodicalId":18043,"journal":{"name":"Linear Algebra and its Applications","volume":"728 ","pages":"Pages 263-282"},"PeriodicalIF":1.1000,"publicationDate":"2025-09-09","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/S0024379525003738","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
Given any finite topological space X and a field , we associate a quadratic space , consisting of a vector space over and a quadratic form , to X. The eigenvalues and signature of are topological invariants of X. We study their relations with X. From this, we obtain restrictions to check whether a finite topological space can be embedded into another one. Additionally, we compute these invariants for minimal finite models of spheres and other families of finite spaces.
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.