Search Results - "Koliha, J.J."

ON THE NORM OF IDEMPOTENTS IN C-ALGEBRAS by KOLIHA, J.J., RAKOČEVIĆ, V.

“…In this paper we study norms of idempotents in C*-algebras. Results of Ljance, Vidav, Buckholtz and Wimmer on idempotent operators in Hilbert spaces are…”
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On Kaufmanʼs theorem by Koliha, J.J.

“…Kaufmanʼs theorem (Kaufman, 1978 [9]) on representing closed linear operators as quotients of bounded operators is given a new constructive proof, and is…”
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Positive solutions to the equations A X = C and X B = D for Hilbert space operators by Dajić, Alegra, Koliha, J.J.

“…The paper studies the equation A X = C for bounded linear operators between Hilbert spaces, gives conditions for the existence of hermitian solutions and…”
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Moore–Penrose inverse in rings with involution by Koliha, J.J., Djordjević, Dragan, Cvetković, Dragana

“…We study the Moore–Penrose inverse (MP-inverse) in the setting of rings with involution. The results include the relation between regular, MP-invertible and…”
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EP elements in rings by Mosić, Dijana, Djordjević, Dragan S., Koliha, J.J.

“…In this paper, we present a number of new characterizations of EP elements in rings with involution in purely algebraic terms, and considerably simplify proofs…”
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Generalized Drazin invertibility of combinations of idempotents by Koliha, J.J., Cvetković-Ilić, Dragana, Deng, Chunyuan

“…The paper serves as a correction to J. Math. Anal. Appl. 359 (2009) 731–738 dealing with the Drazin invertibility of combinations of idempotents p,q in a…”
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Equations ax = c and xb = d in rings and rings with involution with applications to Hilbert space operators by Dajić, Alegra, Koliha, J.J.

“…This paper reviews the equations ax = c and xb = d from a new perspective by studying them in the setting of associative rings with or without involution…”
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The nullity and rank of linear combinations of idempotent matrices by Koliha, J.J., Rakočević, V.

“…Baksalary and Baksalary [J.K. Baksalary, O.M. Baksalary, Nonsingularity of linear combinations of idempotent matrices, Linear Algebra Appl. 388 (2004) 25–29]…”
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The difference and sum of projectors by Koliha, J.J, Rakočević, V, Straškraba, I

“…The aim of this paper is to present new results on the invertibility of the sum of projectors, and new relations between the nonsingularity of the difference…”
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THE a-DRAZIN INVERSE AND ERGODIC BEHAVIOUR OF SEMIGROUPS AND COSINE OPERATOR FUNCTIONS by BUTZER, P.L., KOLIHA, J.J.

“…The paper introduces a special type of a Drazin-like inverse for closed linear operators that arises naturally in ergodic theory of operator semigroups and…”
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Factorization of EP elements in C-algebras by Djordjević, D.S., Koliha, J.J., Straškraba, I.

“…We offer some extensions to C*-algebra elements of factorization properties of EP operators on a Hilbert space…”
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Invertibility of the Difference of Idempotents by Koliha, J.J., Rakočević, V.

“…We study conditions equivalent to the invertibility of f m g when f and g are idempotents in a unital ring, and give applications to bounded linear operators…”
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Error bounds for a general perturbation of the Drazin inverse by Koliha, J.J.

“…The paper solves a long standing problem of finding error bounds for a general perturbation of the Drazin inverse. The bounds are given in terms of the…”
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Invertibility of the Sum of Idempotents by Koliha, J.J., RakoČević, V.

“…We study necessary and sufficient conditions for the invertibility of the sum f+g when f and g are idempotents in a unital ring or bounded linear operators in…”
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CHARACTERIZING HERMITIAN, NORMAL AND EP OPERATORS by Djordjević, Dragan S., Koliha, J. J.

“…In this paper further characterizations of Hermitian, normal and EP operators on Hilbert spaces are established. Thus the recent results of O. M. Baksalary and…”
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Perturbation of the Drazin inverse for matrices with equal eigenprojections at zero by Castro González, N., Koliha, J.J., Wei, Yimin

“…Let A π denote the eigenprojection of a matrix A corresponding to the eigenvalue 0. We characterize matrices B such that B π=A π , and derive from the results:…”
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The Mapping γx, yin Normed Linear Spaces and Applications by Dragomir, S.S., Koliha, J.J.

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A simple proof of the product theorem for EP matrices by Koliha, J.J.

“…We give a simple proof of a recent theorem of Hartwig and Katz on the product of EP matrices…”
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SINGULARLY PERTURBED C0-SEMIGROUPS AND NONHOMOGENEOUS DIFFERENTIAL EQUATIONS IN BANACH SPACES by KOLIHA, J.J., TRAN, TRUNG DINH

“…In this paper we study a singular perturbation of an asymptotically convergent operator C0-semigroup, and describe the spectral behaviour and a power series…”
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THE DRAZIN INVERSE FOR CLOSED LINEAR OPERATORS AND THE ASYMPTOTIC CONVERGENCE OF C0-SEMIGROUPS by KOLIHA, J.J., TRAN, TRUNG DINH

“…The paper defines and studies the Drazin inverse for a closed linear operator A in a Banach space X in the case that 0 is an isolated spectral point of A…”
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