Displaying similar documents to “On the range and the kernel of the elementary operators ∑ i = 1 n A i X B i - X .”

On the Φ class operators.

Bachir, A., Segres, A. (2009)

International Journal of Open Problems in Computer Science and Mathematics. IJOPCM

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Distances between composition operators.

Valentin Matache (2007)

Extracta Mathematicae

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Composition operators C induced by a selfmap φ of some set S are operators acting on a space consisting of functions on S by composition to the right with φ, that is Cf = f º φ. In this paper, we consider the Hilbert Hardy space H on the open unit disk and find exact formulas for distances ||C - C|| between composition operators. The selfmaps φ and ψ involved in those formulas are constant, inner, or analytic selfmaps of the unit disk fixing the origin.

On some shift invariant integral operators, univariate case

George A. Anastassiou, Heinz H. Gonska (1995)

Annales Polonici Mathematici

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In recent papers the authors studied global smoothness preservation by certain univariate and multivariate linear operators over compact domains. Here the domain is ℝ. A very general positive linear integral type operator is introduced through a convolution-like iteration of another general positive linear operator with a scaling type function. For it sufficient conditions are given for shift invariance, preservation of global smoothness, convergence to the unit with rates, shape preserving...

Solutions to a class of polynomially generalized Bers–Vekua equations using Clifford analysis

Min Ku, Uwe Kähler, Paula Cerejeiras (2012)

Archivum Mathematicum

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In this paper a class of polynomially generalized Vekua–type equations and of polynomially generalized Bers–Vekua equations with variable coefficients defined in a domain of Euclidean space are discussed. Using the methods of Clifford analysis, first the Fischer–type decomposition theorems for null solutions to these equations are obtained. Then we give, under some conditions, the solutions to the polynomially generalized Bers–Vekua equation with variable coefficients. Finally, we present...

Functions of operators and their commutators in perturbation theory

Yu. Farforovskaya (1994)

Banach Center Publications

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This paper shows some directions of perturbation theory for Lipschitz functions of selfadjoint and normal operators, without giving precise proofs. Some of the ideas discussed are explained informally or for the finite-dimensional case. Several unsolved problems are mentioned.

Triangular Models and Asymptotics of Continuous Curves with Bounded and Unbounded Semigroup Generators

Kirchev, Kiril, Borisova, Galina (2005)

Serdica Mathematical Journal

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2000 Mathematics Subject Classification: Primary 47A48, Secondary 60G12. In this paper classes of K^r -operators are considered – the classes of bounded and unbounded operators A with equal domains of A and A*, finite dimensional imaginary parts and presented as a coupling of a dissipative operator and an antidissipative one with real absolutely continuous spectra and the class of unbounded dissipative K^r -operators A with different domains of A and A* and with real absolutely...