English

On the maxima of Littlewood polynomials on $[-1,1]$

Probability 2026-05-12 v1 Combinatorics

Abstract

A Littlewood polynomial is a polynomial of the form fn(x)=k=0nεkxk f_n(x)=\sum_{k=0}^n \varepsilon_k x^k with εk{1,1}\varepsilon_k\in\{-1, 1\}. Let (εk)k0(\varepsilon_k)_{k \ge 0} be i.i.d. Rademacher coefficients. We show that the lower envelope of maxx[1,1]fn(x)\max_{x\in[-1,1]}|f_n(x)| is determined by the small-ball probability of a certain Gaussian process. In particular, almost surely, lim infnlog(maxx[1,1]fn(x)/n)(loglogn)1/3=(3π24)1/3. \liminf_{n\to\infty} \frac{\log(\max_{x\in[-1,1]}|f_n(x)|/\sqrt n)}{(\log\log n)^{1/3}} = -\Big(\frac{3\pi^2}{4}\Big)^{1/3}.

Keywords

Cite

@article{arxiv.2604.19294,
  title  = {On the maxima of Littlewood polynomials on $[-1,1]$},
  author = {Brayden Letwin and Mehtaab Sawhney},
  journal= {arXiv preprint arXiv:2604.19294},
  year   = {2026}
}

Comments

29 pages