Approximation by fourier sums and best approximations on classes of analytic functions
We establish asymptotic equalities for upper bounds of approximations by Fourier sums and for the best approximations in the metrics of C and L1 on classes of convolutions of periodic functions that can be regularly extended into a fixed strip of the complex plane.
English version (Springer): Ukrainian Mathematical Journal 52 (2000), no. 3, pp 433-456.
Citation Example: Serdyuk A. S., Stepanets O. I. Approximation by fourier sums and best approximations on classes of analytic functions // Ukr. Mat. Zh. - 2000. - 52, № 3. - pp. 375-395.