This is a survey of recent results on central and non-central limit theorems for quadratic functionals of stationary processes. The underlying processes are Gaussian, linear or Lévy-driven linear processes with memory, and are defined either in discrete or continuous time. We focus on limit theorems for Toeplitz and tapered Toeplitz type quadratic functionals of stationary processes with applications in parametric and nonparametric statistical estimation theory. We discuss questions concerning Toeplitz matrices and operators, Fejér-type singular integrals, and Lévy-Itô-type and Stratonovich-type multiple stochastic integrals. These are the main tools for obtaining limit theorems.
On a Szego Type Limit Theorem, the Holder-Young-Brascamp-Lieb Inequality, and the Asymptotic Theory of Integrals and Quadratic Forms of Stationary Fields
A third-moment theorem and precise asymptotics for variations of stationary Gaussian sequences
在两篇新论文(Bierme等人,2013)和(Nourdin and Peccati,2015),给出了精确的一般定量界以补充著名的Nualart和Peccati的四阶矩定理,通过该定理,固定Wiener混沌中的序列收敛于正规律当且仅当其四阶累积量收敛于$0$ .其界表明,收敛速度与四阶累积量的最大值和三阶矩(累积量)的绝对值是一个数量级。专门的情况下,归一化的中心二次变化的平稳高斯序列,我们表明,第三矩定理成立:收敛发生时,只有当序列的第三时刻趋于$0$。对于具有一般递减协方差的序列,通过使用(Nourdin和Peccati,2015)的结果并找到二次变分的第三和第四累积量收敛到$0$的精确速度来证明这一点。(Nourdin and Peccati,2015)还允许我们对一类对数调制协方差结构的收敛速度进行定量估计,这在研究分数布朗运动的二次变分的收敛性时,将临界Hurst参数的概念放在了正确的位置。我们还研究了收敛速度时的限制是不是高斯,而是一个第二维纳混沌法。使用对数调制类的谱密度,我们恢复Dobrushin-Major/Taqqu的经典结果,其中限制是Rosenblatt法,我们提供了新的收敛速度。在这种情况下的结论是,尽管调制缓慢变化,但为了获得Rosenblatt极限而付出的代价是非常慢的收敛速度,大致与调制相同的阶数。