Hilbert空间上线性算子的Drazin可逆性

主要研究了Hilbert空间上两个Drazin可逆算子和的Drazin可逆性.同时,对上三角算子矩阵的Drazin可逆性也给出了详细的讨论.     

有界线性算子乘积以及和的广义Drazin可逆性

本文讨论了两个有界线性算子的乘积以及和的广义Drazin可逆性及其广义Drazin逆的表达式.在新条件下,采用空间分解的方法证明了算子乘积PQ以及算子和P+Q是广义Drazin可逆的,并给出(PQ)^d和(P+Q)^d的具体表达式.     

Banach空间中线性算子的Drazin广义逆的表示

1981年,1985年,2000年,乔三正、蔡东汉、魏益民分别给出Drazin广义逆不同形式的表示．本文将对上述结果进行推广,给出Drazin广义逆的统一表示,使上述三个结果均成为本文主要结果的特例．在本文主要结果的基础上,利用算子谱理论,给出Drazin广义逆的一种逼近形式的表示,同时给出逼近解的估计．此结果推广了蔡东汉、魏益民的相应结果．     

无界形式Hamilton算子的可逆性

利用算子分块方法研究了具有一般定义域的形式Hamilton算子的可逆性和可逆补,还进一步给出了无穷维Hamilton算子的相关结论.     

Hilbert空间上算子W-加权Drazin逆的刻画及表示

该文研究了Hilbert空间上线性算子的W-加权Drazin逆,利用算子的分块矩阵表示,给出了W-加权Drazin逆的刻画及表示,所获结果推广了魏益民等的相关结果.     

有界线性算子的Drazin逆的逆序律

该文讨论了两个有界线性算子乘积的Drazin可逆性及其逆序律,分别在P与PQP可交换(即P²QP=PQP²)和Q与QPQ可交换(即Q²PQ=QPQ²)等条件下,采用空间分解的方法得到了PQ的Drazin可逆性及其逆序律(PQ)^D=Q^DP^D成立的等价条件.     

两个幂等算子线性组合的Drazin逆

利用空间分解的技巧,在条件PQP=QPQ下,得到两个幂等算子P和Q的多线性组合aP+bQ+cPQ+dQP+ePQP的Drazin逆的表达式.     

四分块算子矩阵Drazin逆的表示

本文研究定义于复Banach空间上的四分块算子矩阵的Drazin逆的表示,此问题是1979年S.L.Campbell和C.D.Meyer提出的公开问题.结果表明主要定理是最近的某些研究进展在不同程度的推广,此外还举例说明了结果的有效性.     

有关p-亚正规算子和对数亚正规算子广义Aluthge变换的一个注解

We shall give some results on generalized aluthge transformation for p-hyponormal and log-hyponormal operators.We shall also discuss the best possibility of these results.     

Banach空间上有界线性算子的Drazin逆的扰动分析

设X为一复域C上的Banach空间,设T:X→X为一有界线性算子,其指标为k且R(T^k)闭.记T的Drazin逆为T^D.设T=T+δT,则在一定条件下,T^D有简明分解式T^D=T^D(I+δTT^D)^-1=(I+T^DδT)^-1T^D,从而导出了相对误差‖T^D-T^D<     

On Drazin invertibility

The left Drazin spectrum and the Drazin spectrum coincide with the upper semi--Browder spectrum and the -Browder spectrum, respectively. We also prove that some spectra coincide whenever or satisfies the single-valued extension property.

     

Positive Invertibility of Nonselfadjoint Operators

The paper deals with a class of nonselfadjoint operators in a separable Hilbert lattice. Conditions for the positive invertibility are derived. Moreover, upper and lower estimates for the inverse operator are established. In addition, bounds for the positive spectrum are suggested. Applications to integral operators, integro-differential operators and infinite matrices are discussed.     

Drazin invertibility of upper triangular operator matrices

In this paper, the existence is considered of a Drazin invertible completion of an upper triangular operator matrix. The proof of a recently published result is corrected.     

Left and right generalized Drazin invertible operators

In this paper, we define and study the left and the right generalized Drazin inverse of bounded operators in a Banach space. We show that the left (resp. the right) generalized Drazin inverse is a sum of a left invertible (resp. a right invertible) operator and a quasi-nilpotent one. In particular, we define the left and the right generalized Drazin spectra of a bounded operator and also show that these sets are compact in the complex plane and invariant under additive commuting quasi-nilpotent perturbations. Furthermore, we prove that a bounded operator is left generalized Drazin invertible if and only if its adjoint is right generalized Drazin invertible. An equivalent definition of the pseudo-Fredholm operators in terms of the left generalized Drazin invertible operators is also given. Our obtained results are used to investigate some relationships between the left and right generalized Drazin spectra and other spectra founded in Fredholm theory.     

p-ω-亚正规算子的一些性质

In this paper,let T be a bounded linear operator on a complex Hilbert H.We give and prove that every p-w-hyponormal operator has Bishop's property(β)and spectral properties;Quasi-similar p-w-hyponormal operators have equal spectra and equal essential spectra.Finally,for p-w-hyponormal operators,we give a kind of proof of its normality by use of properties of partial isometry.     

任意域上的代数中两个幂等元线性组合的Drazin可逆性（英文）

对域上的代数中两个幂等元P和q,满足一定的条件PqP=s,其中s∈{O,P,q,Pq,qP,qPq},本文得到了它们的线性组合ip＋jq均是Drazin可逆的,并给出了其Drazin逆的表示.