English

On Markov-Duffin-Schaeffer inequalities with a majorant. II

Numerical Analysis 2012-10-30 v1

Abstract

We are continuing out studies of the so-called Markov inequalities with a majorant. Inequalities of this type provide a bound for the kk-th derivative of an algebraic polynomial when the latter is bounded by a certain curved majorant μ\mu. A conjecture is that the upper bound is attained by the so-called snake-polynomial which oscillates most between ±μ\pm \mu, but it turned out to be a rather difficult question. In the previous paper, we proved that this is true in the case of symmetric majorant provided the snake-polynomial has a positive Chebyshev expansion. In this paper, we show that that the conjecture is valid under the condition of positive expansion only, hence for non-symmetric majorants as well.

Keywords

Cite

@article{arxiv.1210.7795,
  title  = {On Markov-Duffin-Schaeffer inequalities with a majorant. II},
  author = {Geno Nikolov and Alexei Shadrin},
  journal= {arXiv preprint arXiv:1210.7795},
  year   = {2012}
}