Displaying similar documents to “Cyclic behavior of linear fractional composition operators.”

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.

The algebra generated by a pair of operator weighted shifts

Marek Ptak (1995)

Annales Polonici Mathematici

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We present a model for two doubly commuting operator weighted shifts. We also investigate general pairs of operator weighted shifts. The above model generalizes the model for two doubly commuting shifts. WOT-closed algebras for such pairs are described. We also deal with reflexivity for such pairs assuming invertibility of operator weights and a condition on the joint point spectrum.

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...

Representations and Positive Definite Functions on Hypergroups

Nasr-Isfahani, A. (1999)

Serdica Mathematical Journal

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Some relationships between representations of a hypergroup X, its algebras, and positive definite functions on X are studied. Also, various types of convergence of positive definite functions on X are discussed.