A note on Anderson's theorem in the infinite-dimensional setting

被引:4
|
作者
Birbonshi, Riddhick [1 ]
Spitkovsky, Ilya M. [2 ]
Srivastava, P. D. [1 ]
机构
[1] Indian Inst Technol, Dept Math, Kharagpur 721302, W Bengal, India
[2] NYUAD, Div Sci & Math, POB 129188, Abu Dhabi, U Arab Emirates
关键词
Numerical range; Normal operator; Compact operator; Weighted shift; NUMERICAL RANGE; WEIGHTED SHIFT; SPECTRUM;
D O I
10.1016/j.jmaa.2018.01.002
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
Anderson's theorem states that if the numerical range W(A) of an n-by-n matrix A is contained in the unit disk (D) over bar and intersects with the unit circle at more than n points, then W(A) = (D) over bar. An analogue of this result for compact A in an infinite dimensional setting was established by Gau and Wu. We consider here the case of A being the sum of a normal and compact operator. (C) 2018 Elsevier Inc. All rights reserved.
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页码:349 / 353
页数:5
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