Abstract
This paper is devoted to refining the Bernstein inequality. Let D be the differentiation operator. The action of the operator Λ = D/n on the set of trigonometric polynomials T n is studied: the best constant is sought in the inequality between the measures of the sets {x ∈ T: |Λt(x)| > 1} and {x ∈ T: |t(x)| > 1}. We obtain an upper estimate that is order sharp on the set of uniformly bounded trigonometric polynomials T C n = {t ∈ T n : ‖t‖ ≤ C}.
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Original Russian Text © E.D. Livshits, 2013, published in Trudy Matematicheskogo Instituta imeni V.A. Steklova, 2013, Vol. 280, pp. 215–226.
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Livshits, E.D. A weak-type inequality for uniformly bounded trigonometric polynomials. Proc. Steklov Inst. Math. 280, 208–219 (2013). https://doi.org/10.1134/S0081543813010148
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DOI: https://doi.org/10.1134/S0081543813010148