Reverse Bernstein Inequality on the Circle
Classical Analysis and ODEs
2023-03-09 v2
Abstract
The more then hundred years old Bernstein inequality states that the supremum norm of the derivative of a trigonometric polynomial of fixed degree can be bounded from above by supremum norm of the polynomial itself. The reversed Bernstein inequality, that we prove in this note, says that the reverse inequality holds for functions in the orthogonal complement of the space of polynomials of fixed degree. In fact, we derived a more general result for the lower bounds on higher derivatives. These bounds are better then those obtained by applying bound for the first derivative successively several times.
Keywords
Cite
@article{arxiv.2302.10122,
title = {Reverse Bernstein Inequality on the Circle},
author = {Parvaneh Joharinad and Jürgen Jost and Sunhyuk Lim and Rostislav Matveev},
journal= {arXiv preprint arXiv:2302.10122},
year = {2023}
}
Comments
8 pages, additional references in v2