Generalized cline’s formula for g-Drazin inverse in a ring

In this paper, we give a generalized Cline?s formula for the generalized Drazin inverse. Let R be a ring, and let a, b, c, d ? R satisfying (ac)2 = (db)(ac), (db)2 = (ac)(db), b(ac)a = b(db)a, c(ac)d = c(db)d. Then ac ? Rd if and only if bd ? Rd. In this case, (bd)d = b((ac)d)2d: We also present generalized Cline?s formulas for Drazin and group inverses. Some weaker conditions in a Banach algebra are also investigated. These extend the main results of Cline?s formula on g-Drazin inverse of Liao, Chen and Cui (Bull. Malays. Math. Soc., 37(2014), 37-42), Lian and Zeng (Turk. J. Math., 40(2016), 161-165) and Miller and Zguitti (Rend. Circ. Mat. Palermo, II. Ser., 67(2018), 105-114). As an application, new common spectral property of bounded linear operators over Banach spaces is obtained.

Expressions for the g-Drazin inverse in a Banach algebra

We explore the generalized Drazin inverse in a Banach algebra. Let A be a Banach algebra, and let a,b ? Ad. If ab = ?a?bab? for a nonzero complex number ?, then a + b ? Ad. The explicit representation of (a + b)d is presented. As applications of our results, we present new representations for the generalized Drazin inverse of a block matrix in a Banach algebra. The main results of Liu and Qin [Representations for the generalized Drazin inverse of the sum in a Banach algebra and its application for some operator matrices, Sci. World J., 2015, 156934.8] are extended.

A Seventh-Order Scheme for Computing the Generalized Drazin Inverse

One of the most important generalized inverses is the Drazin inverse, which is defined for square matrices having an index. The objective of this work is to investigate and present a computational tool in the form of an iterative method for computing this task. This scheme reaches the seventh rate of convergence as long as a suitable initial matrix is chosen and by employing only five matrix products per cycle. After some analytical discussions, several tests are provided to show the efficiency of the presented formulation.

Some Results on the Symmetric Representation of the Generalized Drazin Inverse in a Banach Algebra

Based on the conditions a b 2 = 0 and b π ( a b ) ∈ A d , we derive that ( a b ) n , ( b a ) n , and a b + b a are all generalized Drazin invertible in a Banach algebra A , where n ∈ N and a and b are elements of A . By using these results, some results on the symmetry representations for the generalized Drazin inverse of a b + b a are given. We also consider that additive properties for the generalized Drazin inverse of the sum a + b .

Explicit formulae for the generalized drazin inverse of block matrices over a Banach algebra

In this paper, we give expressions for the generalized Drazin inverse of a (2,2,0) block matrix over a Banach algebra under certain circumstances, utilizing which we derive the generalized Drazin inverse of a 2x2 block matrix in a Banach algebra under weaker restrictions. Our results generalize and unify several results in the literature.

Generalized Drazin inverses in a ring

An element a in a ring R has generalized Drazin inverse if and only if there exists b ? comm2(a) such that b = b2a,a-a2b ? Rqnil. We prove that a ? R has generalized Drazin inverse if and only if there exists p3 = p ? comm2(a) such that a + p ? U(R) and ap 2 Rqnil. An element a in a ring R has pseudo Drazin inverse if and only if there exists b ? comm2(a) such that b = b2a,ak-ak+1b ? J(R) for some k 2 N. We also characterize pseudo inverses by means of tripotents in a ring. Moreover, we prove that a ? R has pseudo Drazin inverse if and only if there exists b ? comm2(a) and m,k ? N such that bm = bm+1a,ak-ak+1b ? J(R).