Abstract
By using the classical Hadamard theorem, we obtain an exact (in a certain sense) inequality for the best polynomial approximations of an analytic function f(z) from the Hardy space H p, p ≥ 1, in disks of radii ρ, ρ1, and ρ2, 0 < ρ1 < ρ < ρ2 < 1.
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Vakarchuk, S.B. Relationship between the Hadamard Theorem on Three Disks and Certain Problems of Polynomial Approximation of Analytic Functions. Ukrainian Mathematical Journal 53, 283–288 (2001). https://doi.org/10.1023/A:1010473205554
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DOI: https://doi.org/10.1023/A:1010473205554