Real Roots of Random Weyl Polynomials with General Coefficients: Expectation and Variance

Fuente: arXiv
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Main Authors: Aguirre, Ander, Nguyen, Hoi H., Wang, Jingheng
Format: Preprint
Published: 2025
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author Aguirre, Ander
Nguyen, Hoi H.
Wang, Jingheng
author_facet Aguirre, Ander
Nguyen, Hoi H.
Wang, Jingheng
contents In this paper, we investigate the number of real zeros of random Weyl polynomials of degree \(n \to \infty\) with general coefficient distributions. Motivated by the results of arXiv:1409.4128 and arXiv:1402.4628 as well as arXiv:1711.03316 and arXiv:1912.11901, we determine how the expected number of real zeros and their variance, over various natural intervals, depend on the moments of the common coefficient distribution. Our main finding is that while the first-order asymptotic of the expectation is universal, the next-order correction depends on the third and fourth moments of the distribution, and may grow linearly with \(\log n\), depending on the interval under consideration. In contrast, for the variance we show that the leading-order term is universal, which differs from the behavior observed for random trigonometric polynomials in arXiv:1711.03316 and arXiv:1912.11901. Our approach relies on an Edgeworth expansion for random walks arising from Weyl polynomials, a result of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2511_07735
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Real Roots of Random Weyl Polynomials with General Coefficients: Expectation and Variance
Aguirre, Ander
Nguyen, Hoi H.
Wang, Jingheng
Probability
In this paper, we investigate the number of real zeros of random Weyl polynomials of degree \(n \to \infty\) with general coefficient distributions. Motivated by the results of arXiv:1409.4128 and arXiv:1402.4628 as well as arXiv:1711.03316 and arXiv:1912.11901, we determine how the expected number of real zeros and their variance, over various natural intervals, depend on the moments of the common coefficient distribution. Our main finding is that while the first-order asymptotic of the expectation is universal, the next-order correction depends on the third and fourth moments of the distribution, and may grow linearly with \(\log n\), depending on the interval under consideration. In contrast, for the variance we show that the leading-order term is universal, which differs from the behavior observed for random trigonometric polynomials in arXiv:1711.03316 and arXiv:1912.11901. Our approach relies on an Edgeworth expansion for random walks arising from Weyl polynomials, a result of independent interest.
title Real Roots of Random Weyl Polynomials with General Coefficients: Expectation and Variance
topic Probability
url https://arxiv.org/abs/2511.07735