$K$ -функціонали та екстремальні задачі теорії апроксимації класів аналітичних у крузі функцій. I

S. B. Vakarchuk; M. B. Vakarchuk

doi:10.37863/umzh.v74i4.6980

S. B. Vakarchuk Alfred Nobel University, Dnipro
M. B. Vakarchuk Oles Honchar Dnipro National University

DOI: https://doi.org/10.37863/umzh.v74i4.6980

Abstract

УДК 517.5

Based on the Hadamard composition in the Hardy, Bergman and Gvaradze Banach spaces of functions analytic in the unit circle, we consider a generalization of the $K$-functional. In solving some extreme problems of the theory of approximation in the complex plane, we obtain certain exact results in the case where the indicated $K$-functional is used as a characteristic of smoothness.

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$K$-functionals and extreme problems of the theory of approximation for classes of analytic functions in the circle. I

Abstract

References