论文标题

KAC-Geronimus多项式的预期实际零数量的渐近扩展

An asymptotic expansion for the expected number of real zeros of Kac-Geronimus polynomials

论文作者

Aljubran, Hanan, Yattselev, Maxim L.

论文摘要

令$ \ {φ_i(z;α)\} _ {i = 0}^\ infty $,对应于$α\ in(-1,1)$,是正式的geronimus polynomials。我们研究了预期的真实零数量的渐近行为,例如$ \ mathbb e_n(α)$,是随机多项式的\ [p_n(z):= \ sum_ {i = 0}^nη_i或标准高斯随机变量。当$α= 0 $时,$φ_i(z; 0)= z^i $和$ p_n(z)$称为kac多项式。在这种情况下,威尔金斯表明$ \ mathbb e_n(0)$承认表格的渐近扩展\ [\ mathbb e_n(0)\ sim \ sim \frac2π\ log(n+1)+sum_+sum_+sum_ {p = 0}在这项工作中,我们获得了$ \ Mathbb e(α)$的类似扩展,以$α\ neq 0 $。事实证明,在这种情况下,渐近学的领先术语是$(1/π)\ log(n+1)$。

Let $ \{φ_i(z;α)\}_{i=0}^\infty $, corresponding to $ α\in(-1,1) $, be orthonormal Geronimus polynomials. We study asymptotic behavior of the expected number of real zeros, say $ \mathbb E_n(α) $, of random polynomials \[ P_n(z) := \sum_{i=0}^nη_iφ_i(z;α), \] where $ η_0,\dots,η_n $ are i.i.d. standard Gaussian random variables. When $ α=0 $, $ φ_i(z;0)=z^i $ and $ P_n(z)$ are called Kac polynomials. In this case it was shown by Wilkins that $ \mathbb E_n(0)$ admits an asymptotic expansion of the form \[ \mathbb E_n(0) \sim \frac2π\log(n+1) + \sum_{p=0}^\infty A_p(n+1)^{-p} \] (Kac himself obtained the leading term of this expansion). In this work we obtain a similar expansion of $ \mathbb E(α) $ for $ α\neq 0 $. As it turns out, the leading term of the asymptotics in this case is $ (1/π)\log(n+1) $.

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