Abstract
We have obtained the exact value of the upper bound on the best approximations in the metric of L on the classes WrHω of functionsf ∈C r2π for which ¦f (r) (x′)-f (r) (x″)”) ¦ <ω(¦ x′-x″f) [ω (t) is the upwards-convex modulus of continuity] by subspaces of r-th order polynomial splines of defect 1 with respect to the partitioning kπ/n.
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Translated from Matematicheskie Zametki, Vol. 20, No. 5, pp. 655–664, November, 1976.
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Korneichuk, N.P. Best approximation by splines on classes of periodic functions in the metric of L. Mathematical Notes of the Academy of Sciences of the USSR 20, 927–933 (1976). https://doi.org/10.1007/BF01146912
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DOI: https://doi.org/10.1007/BF01146912