首页 | 本学科首页   官方微博 | 高级检索  
     检索      


On local irreducibility of the spectrum
Authors:Constantin Costara  Thomas Ransford
Institution:Faculty of Mathematics and Informatics, Ovidius University of Constanta, Mamaia Boul. No. 124, 900527, Romania ; Département de mathématiques et de statistique, Université Laval, Québec (QC), Canada G1K 7P4
Abstract:Let $ \mathcal M_n$ be the algebra of $ n\times n$ complex matrices, and for $ x\in\mathcal M_n$ denote by $ \sigma(x)$ and $ \rho(x)$ the spectrum and spectral radius of $ x$ respectively. Let $ D$ be a domain in $ \mathcal M_n$ containing 0, and let $ F:D\to\mathcal M_n$ be a holomorphic map. We prove: (1) if $ \sigma(F(x))\cap\sigma(x)\ne\emptyset$ for $ x\in D$, then $ \sigma(F(x))=\sigma(x)$ for $ x\in D$; (2) if $ \rho(F(x))=\rho(x)$ for $ x\in D$, then again $ \sigma(F(x))=\sigma(x)$ for $ x\in D$. Both results are special cases of theorems expressing the irreducibility of the spectrum $ \sigma(x)$ near $ x=0$.

Keywords:Spectrum  algebroid multifunction  irreducible  spectral radius  preserver
点击此处可从《Proceedings of the American Mathematical Society》浏览原始摘要信息
点击此处可从《Proceedings of the American Mathematical Society》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号