{"title":"On trace zero symplectic matrices","authors":"Ralph John L. de la Cruz, Kae Mark T. Domingo","doi":"10.1016/j.laa.2025.06.011","DOIUrl":null,"url":null,"abstract":"<div><div>It is known that every 2<em>n</em>-by-2<em>n</em> complex matrix <em>A</em> is a sum of three symplectic matrices. We show that if <em>A</em> has zero trace, then the summands may be taken to have zero trace as well. We prove an analogous result for real matrices. We also characterize 2-by-2 real matrices that can be written as a sum of two trace zero symplectic matrices.</div></div>","PeriodicalId":18043,"journal":{"name":"Linear Algebra and its Applications","volume":"724 ","pages":"Pages 192-205"},"PeriodicalIF":1.0000,"publicationDate":"2025-06-18","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/S0024379525002630","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
It is known that every 2n-by-2n complex matrix A is a sum of three symplectic matrices. We show that if A has zero trace, then the summands may be taken to have zero trace as well. We prove an analogous result for real matrices. We also characterize 2-by-2 real matrices that can be written as a sum of two trace zero symplectic 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.