It is shown that the lower bounds of the Kolmogorov widths d 2n in the space C established in the first part of our work for the function classes that can be represented in the form of convolutions of the kernels \( {H}_{h,\beta }(t)={\displaystyle \sum_{k=1}^{\infty}\frac{1}{ \cosh kh} \cos \left(kt-\frac{\beta \pi }{2}\right),\kern1em h>0,\kern1em \beta \in \mathbb{R},} \) with functions φ ⊥ 1 from the unit ball in the space L ∞ coincide (for all n ≥ nh) with the best uniform approximations of these classes by trigonometric polynomials whose order does not exceed n − 1. As a result, we obtain the exact values of widths for the indicated classes of convolutions. Moreover, for all n ≥ nh, we determine the exact values of the Kolmogorov widths d 2n−1 in the space L 1 of classes of the convolutions of functions φ ⊥ 1 from the unit ball in the space L 1 with the kernel H h,β .
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Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 67, No. 8, pp. 1011–1018, August, 2015.
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Bodenchuk, V.V., Serdyuk, A.S. Exact Values of Kolmogorov Widths for the Classes of Analytic Functions. II. Ukr Math J 67, 1137–1145 (2016). https://doi.org/10.1007/s11253-016-1141-5
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DOI: https://doi.org/10.1007/s11253-016-1141-5