English

A generalization of a theorem of Brass and Schmeisser

Classical Analysis and ODEs 2023-08-28 v1

Abstract

Let nn be an odd positive integer. It was proved by Brass and Schmeisser that for every quadrature Q=α1f(x1)++αmf(xm),\mathcal{Q}=\alpha_1f(x_1)+\dots+\alpha_mf(x_m), (with positive weights) of order at least n+1n+1 and for every nn-convex function f,f, the value of QQ on ff lies between the values of Gauss and Lobatto quadratures of order n+1n+1 calculated for the same function ff. We generalize this result in two directions, replacing QQ by an integral with respect to a given measure and allowing the number nn to any positive integer (for even nn Radau quadratures replace Gauss and Lobatto ones

Keywords

Cite

@article{arxiv.2308.13216,
  title  = {A generalization of a theorem of Brass and Schmeisser},
  author = {Tomasz Szostok},
  journal= {arXiv preprint arXiv:2308.13216},
  year   = {2023}
}