On the Sharpness of a Jackson Estimate b
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L. Imhof
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Article
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1996
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Elsevier Science
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English
β 412 KB
Using ideas of Gru nwald, Marcinkiewicz, and Ve rtesi concerning the divergence of interpolation processes, a counterexample is constructed which establishes that a Jackson estimate for the best approximation by algebraic polynomials given by Ditzian and Totik is sharp in a pointwise sense everywher