Abstract
We study properties of generalized K-functionals and generalized moduli of smoothness in Lp(ℝ) spaces with 1 ≤ p < ∞ as well as in the space C(ℝ) of uniformly continuous and bounded functions. We obtain direct Jackson-type estimates and inverse Bernstein-type estimates. We show the equivalence between approximation error of convolution integrals generated by an arbitrary generator with compact support, generalized K-functionals generated by homogeneous functions and generalized moduli of smoothness. Our approach covers classical approximation methods, K-functionals related to fractional derivatives and fractional moduli of smoothness.
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The first named author was partially supported by the grant of the President of Russian Federation for young candidates of sciences, project no. MK-176.2017.1.
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Artamonov, S., Runovski, K. & Schmeisser, HJ. Approximation By Bandlimited Functions, Generalized K-Functionals and Generalized Moduli of Smoothness. Anal Math 45, 1–24 (2019). https://doi.org/10.1007/s10476-018-0302-1
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DOI: https://doi.org/10.1007/s10476-018-0302-1