Numerical radius and unitarity

被引：0
|
作者：
Takashi Sano
Atsushi Uchiyama
机构：
[1] Yamagata University,Department of Mathematical Sciences, Faculty of Science
来源：
Acta Scientiarum Mathematicarum | 2010年 / 76卷 / 3-4期
关键词：
numerical radius; unitary operator; numerical range; 47A12; 47A63;
D O I：
10.1007/BF03549843
中图分类号：
学科分类号：
摘要：
We show that an invertible operator A is unitary if the numerical radius satisfies w(A)≦1 and w(A−1)≦1.
引用
收藏
页码：581 / 584
页数：3
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