Abstract
We determine the exact value of the best linear polynomial approximation of a unit ball of the Hardy space H p, 1 ≤ p ≤ ∞, on concentric circles \(\mathbb{T}\rho={z \in \mathbb{C}:|z|=\rho}\), 0 ≤ ρ < 1, in the uniform metric. We construct the best linear method of approximation and prove the uniqueness of this method.
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Savchuk, V.V. Best Linear Methods of Approximation of Functions of the Hardy Class H p . Ukrainian Mathematical Journal 55, 1110–1118 (2003). https://doi.org/10.1023/B:UKMA.0000010609.60573.05
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DOI: https://doi.org/10.1023/B:UKMA.0000010609.60573.05