{"title":"On the fibers of the principal minor map and an application to stable polynomials","authors":"Abeer Al Ahmadieh","doi":"10.1016/j.jalgebra.2025.07.030","DOIUrl":null,"url":null,"abstract":"<div><div>This paper explores the fibers of the principal minor map over an arbitrary field. The principal minor map assigns to each <span><math><mi>n</mi><mo>×</mo><mi>n</mi></math></span> matrix the <span><math><msup><mrow><mn>2</mn></mrow><mrow><mi>n</mi></mrow></msup></math></span>-vector of its principal minors. In 1984, Hartfiel and Loewy proposed a condition that was sufficient to ensure that the fiber of the principal minor map is a single point up to diagonal equivalence. Loewy later improved upon this condition in 1986. In this paper, we provide a necessary and sufficient condition for the fiber to be a point up to diagonal equivalence. Additionally, we establish a connection between the reducibility of a matrix and the reducibility of its determinantal representation. Using this connection, we fully characterize the fibers that contain a symmetric or Hermitian matrix in the space of <span><math><mi>n</mi><mo>×</mo><mi>n</mi></math></span> matrices over any field. We also use these techniques to answer a question of Borcea, Brändén, and Liggett concerning real stable matrices.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"685 ","pages":"Pages 46-61"},"PeriodicalIF":0.8000,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Algebra","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0021869325004491","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
This paper explores the fibers of the principal minor map over an arbitrary field. The principal minor map assigns to each matrix the -vector of its principal minors. In 1984, Hartfiel and Loewy proposed a condition that was sufficient to ensure that the fiber of the principal minor map is a single point up to diagonal equivalence. Loewy later improved upon this condition in 1986. In this paper, we provide a necessary and sufficient condition for the fiber to be a point up to diagonal equivalence. Additionally, we establish a connection between the reducibility of a matrix and the reducibility of its determinantal representation. Using this connection, we fully characterize the fibers that contain a symmetric or Hermitian matrix in the space of matrices over any field. We also use these techniques to answer a question of Borcea, Brändén, and Liggett concerning real stable matrices.
期刊介绍:
The Journal of Algebra is a leading international journal and publishes papers that demonstrate high quality research results in algebra and related computational aspects. Only the very best and most interesting papers are to be considered for publication in the journal. With this in mind, it is important that the contribution offer a substantial result that will have a lasting effect upon the field. The journal also seeks work that presents innovative techniques that offer promising results for future research.