自然科学版
陕西师范大学学报(自然科学版)
数学与计算机科学
单值延拓性质与广义 (ω)性质
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戴磊,曹小红*
(陕西师范大学 数学与信息科学学院, 陕西 西安 710062)
戴磊, 男, 博士研究生, 研究方向为算子代数与算子理论.E-mail:leidai@yeah.net.*通信作者:曹小红,女,教授,博士.E-mail:xiaohongcao@snnu.edu.cn.
摘要:
研究了Banach空间X上有界线性算子T的广义(ω1)性质及广义(ω)性质. 利用单值延拓性质, 给出了算子T∈B(X)有广义(ω1)性质的充要条件.证明了:若T*在λσSBF-+(T)有单值延拓性质, 则T∈B(X)有广义(ω)性质当且仅当下列之一成立:(1)对任意λ∈E(T), 存在n∈N, 使得H0(T-λ)= N[(T-λ)n]; (2)对任意λ∈E(T), 存在n∈N, 使得R[(T-λ)n]闭; (3)对任意λ∈E(T), 存在n∈N, 使得K(T-λ)=R[(T-λ)n]; (4)对任意λ∈E(T), 存在n∈N, 使得r(Tn)不连续; (5)对任意λ∈E(T),des(T-λ)<∞;(6) E(T)=π(T). 其中E(T)和π(T)分别表示T的谱集中孤立的特征值全体和T的极点全体.
关键词:
广义(ω1)性质; 广义(ω)性质; 单值延拓性质; 谱
收稿日期:
2010-06-28
中图分类号:
O177.2
文献标识码:
A
文章编号:
1672-4291(2011)02-0017-06
基金项目:
国家自然科学基金资助项目(10726043); 中央高校基本科研业务费专项资金项目(GK200901015).
Doi:
The single valued extension property and generalized property (ω)
DAI Lei, CAO Xiao-hong*
(College of Mathematics and Information Science,Shaanxi Normal University, Xi′an 710062, Shaanxi, China)
Abstract:
The generalized property (ω1) and generalized property (ω) for a bounded linear operator T defined on a Banach space are studied. A sufficient and necessary condition for an operator to nave the generalized property (ω1) is given by means of single-valued extension property(SVEP). It is proved that if T* has the SVEP at all points λσSBF-+(T), then T satisfies the generalized property (ω) if and only if one of the following conditions is satisfied: (1) there exists n∈N such that H0(T-λ)=N[(T-λ)n] for every λ∈E(T); (2) there exists n∈N such that R[(T-λ)n] is closed for every λ∈E(T); (3) there exists n∈N such that K(T-λ)=R[(T-λ)n] for every λ∈E(T); (4) there exists n∈N such that r(Tn) is discontinuous at every λ∈E(T); (5) des (T-λ)
KeyWords:
generalized property (ω1); generalized property (ω); single valued extension property; spectrum