English

Inverse Bernstein inequalities and min-max-min problems on the unit circle

Metric Geometry 2015-09-23 v1

Abstract

We give a short and elementary proof of an inverse Bernstein-type inequality found by S. Khrushchev for the derivative of a polynomial having all its zeros on the unit circle. The inequality is used to show that equally-spaced points solve a min-max-min problem for the logarithmic potential of such polynomials. Using techniques recently developed for polarization (Chebyshev-type) problems, we show that this optimality also holds for a large class of potentials, including the Riesz potentials 1/rs1/r^s with s>0.s>0.

Keywords

Cite

@article{arxiv.1307.4056,
  title  = {Inverse Bernstein inequalities and min-max-min problems on the unit circle},
  author = {Tamás Erdélyi and Douglas P. Hardin and Edward B. Saff},
  journal= {arXiv preprint arXiv:1307.4056},
  year   = {2015}
}
R2 v1 2026-06-22T00:51:49.330Z