Average Nikolskii factors for random trigonometric polynomials

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Ling, Yun, Geng, Jiaxin, Li, Jiansong, Wang, Heping
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866909547195531264
author Ling, Yun
Geng, Jiaxin
Li, Jiansong
Wang, Heping
author_facet Ling, Yun
Geng, Jiaxin
Li, Jiansong
Wang, Heping
contents For $1\le p,q\le \infty$, the Nikolskii factor for a trigonometric polynomial $T_{\bf a}$ is defined by $$\mathcal N_{p,q}(T_{\bf a})=\frac{\|T_{\bf a}\|_{q}}{\|T_{\bf a}\|_{p}},\ \ T_{\bf a}(x)=a_{1}+\sum\limits^{n}_{k=1}(a_{2k}\sqrt{2}\cos kx+a_{2k+1}\sqrt{2}\sin kx).$$ We study this average Nikolskii factor for random trigonometric polynomials with independent $N(0,σ^{2})$ coefficients and obtain that the exact order. For $1\leq p<q<\infty$, the average Nikolskii factor is order degree to the 0, as compared to the degree $1/p-1/q$ worst case bound. We also give the generalization to random multivariate trigonometric polynomials.
format Preprint
id arxiv_https___arxiv_org_abs_2503_16786
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Average Nikolskii factors for random trigonometric polynomials
Ling, Yun
Geng, Jiaxin
Li, Jiansong
Wang, Heping
Classical Analysis and ODEs
26D05, 42A05
For $1\le p,q\le \infty$, the Nikolskii factor for a trigonometric polynomial $T_{\bf a}$ is defined by $$\mathcal N_{p,q}(T_{\bf a})=\frac{\|T_{\bf a}\|_{q}}{\|T_{\bf a}\|_{p}},\ \ T_{\bf a}(x)=a_{1}+\sum\limits^{n}_{k=1}(a_{2k}\sqrt{2}\cos kx+a_{2k+1}\sqrt{2}\sin kx).$$ We study this average Nikolskii factor for random trigonometric polynomials with independent $N(0,σ^{2})$ coefficients and obtain that the exact order. For $1\leq p<q<\infty$, the average Nikolskii factor is order degree to the 0, as compared to the degree $1/p-1/q$ worst case bound. We also give the generalization to random multivariate trigonometric polynomials.
title Average Nikolskii factors for random trigonometric polynomials
topic Classical Analysis and ODEs
26D05, 42A05
url https://arxiv.org/abs/2503.16786