摘要
如果Hilbert空间上一个有界线性算子的谱的凸壳等于数值城的闭包,则它称为凸型算子。本文利用谱半径和数值半径给出了凸型算子的一个完全刻划,该刻划包含了Istratescu的结果。
A bounded linear operator on a Hilbert space is said to be convexoid, if the convex hull of its spectrum is equal to the closure of its numerical range. In this paper convexoid operators are completely characterized with their spectral radii and numerical radii, which contains a result in [3].
出处
《吉林大学自然科学学报》
CAS
CSCD
1992年第3期47-49,共3页
Acta Scientiarum Naturalium Universitatis Jilinensis
基金
国家自然科学基金
关键词
凸型算子
数值域
谱
半径
H空间
convexoid operator
numerical range
spectral radius
numerical radius
