English

Lower bounds for Kolmogorov widths of classes of Poisson integrals

Classical Analysis and ODEs 2013-05-24 v2

Abstract

We expand the ranges of permissible values of nn (nNn\in\mathbb{N}) for which Poisson kernels Pq,β(t)=k=1qkcos(ktβπ2)P_{q,\beta}(t)=\sum\limits_{k=1}^{\infty}q^k\cos\left(kt-\dfrac{\beta\pi}{2}\right), q(0,1){q\in(0,1)}, βR\beta\in\mathbb{R}, satisfy Kushpel's condition Cy,2nC_{y,2n}. As a consequence, we obtain exact values for Kolmogorov widths in the space CC (LL) of classes Cβ,qC_{\beta,\infty}^q (Cβ,1qC_{\beta,1}^q) of Poisson integrals generated by kernels Pq,β(t)P_{q,\beta}(t) in new situations. It is shown that obtained here results we can't obtain by using methods of finding of exact lower bounds for widths suggested by A. Pinkus.

Keywords

Cite

@article{arxiv.1304.0650,
  title  = {Lower bounds for Kolmogorov widths of classes of Poisson integrals},
  author = {A. S. Serdyuk and V. V. Bodenchuk},
  journal= {arXiv preprint arXiv:1304.0650},
  year   = {2013}
}

Comments

14 pages, in Ukrainian