{"title":"The joint numerical range of commuting matrices","authors":"Pan-shun Lau, Chi-Kwong Li, Y. Poon","doi":"10.4064/sm200622-31-5","DOIUrl":null,"url":null,"abstract":". It is shown that for n ≤ 3 the joint numerical range of a family of commuting n × n complex matrices is always convex; for n ≥ 4 there are two commuting matrices whose joint numerical range is not convex.","PeriodicalId":51179,"journal":{"name":"Studia Mathematica","volume":"1 1","pages":""},"PeriodicalIF":0.7000,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Studia Mathematica","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.4064/sm200622-31-5","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 2
Abstract
. It is shown that for n ≤ 3 the joint numerical range of a family of commuting n × n complex matrices is always convex; for n ≥ 4 there are two commuting matrices whose joint numerical range is not convex.
期刊介绍:
The journal publishes original papers in English, French, German and Russian, mainly in functional analysis, abstract methods of mathematical analysis and probability theory.