态射和的Drazin逆

设C 是加法范畴, 态射φ,η： X→ X 是C上的态射. 若φ,η 具有Drazin逆且φη =0, 则φ+η 也具有Drazin逆. 若φ具有Drazin逆φ^D 且1_X+φ^Dη 可逆, 作者讨论f =φ+η 的Drazin逆( 群逆)并且给出 f ^D(f ^#}=(1_X+φ^Dη)^-1φ^D的充分必要条件. 最后, 把Huylebrouck的结果从群逆推广到了Drazin逆.     

具有泛分解的态射的广义逆

本文研究范畴中态射乘积ggq的广义逆．假设有态射p'和q',使得p'pg＝g＝gqq'．分别用g~+和g~#给出了乘积Pgq的Moore－Penrose逆和Drazin逆存在的充要条件及其表达式．     

分块态射的广义逆

ClineRE给出了分块矩阵的Moore-Penrose逆的表达式,PetrPeska引进了分块态射的记号且导出了分块态射的Moore-Penrose逆的表达式.本文中,我们推广了Cline型分块态射的记号并得到了Cline型分块态射的Moore-Penrose逆和Drazin逆以及群逆的表达式.     

态射的Draxin逆

本文研究了范畴中态射的Ｄｒａｚｉｎ逆，给出了一般范畴中态射的｛１＾ｍ，２，５｝逆的一个等价刻划。在Ａｂｅｌ范畴中，建立了指数与Ｄｒａｚｉｎ逆的概念，证明了有Ｄｒａｘｉｎ逆的态射必有柱心－幂零分解。     

态射的Drazin逆

本文研究范畴中态射的Ｄｒａｚｉｎ逆．给出了一般范畴中态射的｛１ｍ，２，５｝逆的一个等价刻划．在Ａｂｅｌ范畴中，建立指数与Ｄｒａｚｉｎ逆的概念，证明了有Ｄｒａｚｉｎ逆的态射必有柱心－幂零分解．     

布尔矩阵的Cline逆

研究了布尔矩阵的广义逆,首先引入了布尔矩阵的Drazin逆及Cline逆,利用布尔矩阵的性质证明了任意布尔矩阵均有Drazin逆,从而证得任意布尔矩阵均有Cline逆,且Cline唯一.而且,在A+存在的情况下Ac=A+.最后证明了Cline逆的一些性质.     

具有核的态射的 w -加权Drazin逆

该文中, a: X→Y, w: Y→ X为加法范畴 £ 中的态射, k₁: K ₁→X是(aw)ⁱ 的核, k₂: K₂ →Y是(wa)^j 的核. 那么下列命题等价: (1) a 在 £ 中有w -加权Drazin逆a _d,w; (2) ₁:X→ L₁是(aw)ⁱ 的上核,k_{1 1}(aw)ⁱ⁺¹}+ ₁(k_{1 1})^-1k₁是可逆的; (3) ₂: Y→ L₂是(wa)^j 的上核, k_{2 2}和(wa)^j+1+ ₂(k_{2 2})^-1k₂是可逆的. 作者又研究了具有{1} -逆的正合加法范畴中态射的w -加权Drazin逆的柱心幂零分解, 证明了其存在性. 作者把具有核的态射的Drazin逆及其柱心幂零分解推广到具有核的态射的w -加权 Drazin逆及其柱心幂零分解, 并给出了表达式.     

有界线性算子和的Drazin逆表示

本文讨论了两个有界线性算子和的Drazin可逆性及其表达式.在PQ~3=0,P~2Q=0,QPQ~2=0的条件下,采用预解式的Laurent展开方法,证明了P+Q是Drazin可逆的,并得到了P+Q的Drazin逆的表达式.同时,还确定出P+Q的指标的范围ind(P+Q)≤2t+r+s—1,给出数值算例说明结论的有效性.     

Banach代数上广义Drazin逆的扰动

我们利用分块技术得到了扰动后元素广义Drazin可逆的充要条件,还研究了Banach代数上广义Drazin逆的扰动以及给出了扰动界.     

一类矩阵的Drazin逆

本得到了一类环上矩阵Drazin的一个定理：设N表有单位元环R中零元、可逆元集合与R的中心Z(R)的交集，M表R的子域与Z（R)的交集，A∈Rn×n，若f(λ)=cλ(1-λq(λ))是A的化零多项式，其中q(λ)的系数属于N，且c∈N，则A的Drazin逆存在，且X=A^k[q(A)]k 1是A的唯一的一个Drazin逆。     

Least Squares Properties of Generalized Inverses

The aim of this paper is to systematize solutions of some systems of linear equations in terms of generalized inverses.As a significant application of the Moore-Penrose inverse,the best approximation solution to linear matrix equations (i.e.both least squares and the minimal norm) is considered.Also,characterizations of least squares solution and solution of minimum norm are given.Basic properties of the Drazin-inverse solution and the outer-inverse so-lution are present.Motivated by recent research,important least square prop-erties of composite outer inverses are collected.     

Least Squares Properties of Generalized Inverses

The aim of this paper is to systematize solutions of some systems of linear equations in terms of generalized inverses.As a significant application of the Moore-Penrose inverse,the best approximation solution to linear matrix equations (i.e.both least squares and the minimal norm) is considered.Also,characterizations of least squares solution and solution of minimum norm are given.Basic properties of the Drazin-inverse solution and the outer-inverse so-lution are present.Motivated by recent research,important least square prop-erties of composite outer inverses are collected.     

集合H上矩阵A的左(右)逆、伪左(右)逆

以集合 S与空集Φ的交、并运算为背景 ,定义集合 H ={ 0 ,1 }中的加法与乘法运算 0 ,并考虑 H上一个 s×n级矩阵的左逆矩阵、右逆矩阵以及伪左逆矩阵、伪右逆矩阵的定义 ,并且证明了矩阵 A有左、右逆矩阵 ,A有伪左、右逆矩阵的充分必要条件 .     

Core–EP inverse

In this work, we introduce a notion of ‘core–EP inverse’ for a square matrix which is not essentially of index one. This extends the notion of ‘core inverse’, which was initially defined for the matrices of index one. The properties of matrices having ‘core–EP inverse’ and ‘core–EP generalized inverse’ are studied, and obtained a formula to compute the core–EP generalized inverse from a particular linear combination of minors of given matrix.     

The Pseudo Drazin inverses in Banach Algebras

Let (A) be a complex Banach algebra and J be the Jacobson radical of(A).(1) We firstly show that a is generalized Drazin invertible in (A) if and only if a+J is generalized Drazin invertible in (A)/J.Then we prove that a is pseudo Drazin invertible in (A) if and only if a + J is Drazin invertible in (A)/J.As its application,the pseudo Drazin invertibility of elements in a Banach algebra is explored.(2) The pseudo Drazin order is introduced in (A).We give the necessary and sufficient conditions under which elements in (A) have pseudo Drazin order,then we prove that the pseudo Drazin order is a pre-order.     

Representations and properties of the W-Weighted Drazin inverse

Several new representations of the W-weighted Drazin inverse are introduced. These representations are expressed in terms of various matrix powers as well as in terms of matrix products involving the Moore–Penrose inverse and the usual matrix inverse. Also, the properties of various generalized inverses which arise from derived representations are investigated. The computational complexity and efficiency of the proposed representations are considered. Representations are tested and compared among themselves in a substantial number of randomly generated test examples.     

The group inverse of a product

In this paper, we characterize the existence and give an expression of the group inverse of a product of two regular elements by means of a ring unit.     

Approximation Theorems of Moore-Penrose Inverse by Outer Inverses

1 Introduction and preliminaries Let X and Y be two Hilbert spaces and T a bounded linear operator from X into Y . We use D(T ), N(T ) and R(T ), respectively, to denote the domain, null space and range of T . Recall that a linear operator T # : Y → X is…     

Pseudo core inverses in rings with involution

Let R be a ring with involution. In this paper, we introduce a new type of generalized inverse called pseudo core inverse in R. The notion of core inverse was introduced by Baksalary and Trenkler for matrices of index 1 in 2010 and then it was generalized to an arbitrary ?-ring case by Raki?, Din?i? and Djordjevi? in 2014. Our definition of pseudo core inverse extends the notion of core inverse to elements of an arbitrary index in R. Meanwhile, it generalizes the notion of core-EP inverse, introduced by Manjunatha Prasad and Mohana for matrices in 2014, to the case of ?-ring. Some equivalent characterizations for elements in R to be pseudo core invertible are given and expressions are presented especially in terms of Drazin inverse and {1,3}-inverse. Then, we investigate the relationship between pseudo core inverse and other generalized inverses. Further, we establish several properties of the pseudo core inverse. Finally, the computations for pseudo core inverses of matrices are exhibited.