English

CLT for linear eigenvalue statistics for a tensor product version of sample covariance matrices

Probability 2017-01-27 v2

Abstract

For k,m,nNk,m,n\in \mathbb{N}, we consider nk×nkn^k\times n^k random matrices of the form Mn,m,k(y)=α=1mταYαYαT,Yα=yα(1)...yα(k), \mathcal{M}_{n,m,k}(\mathbf{y})=\sum_{\alpha=1}^m\tau_\alpha {Y_\alpha}Y_\alpha^T,\quad Y_\alpha=\mathbf{y}_\alpha^{(1)}\otimes...\otimes\mathbf{y}_\alpha^{(k)}, where τα\tau _{\alpha }, α[m]\alpha\in[m], are real numbers and yα(j)\mathbf{y}_\alpha^{(j)}, α[m]\alpha\in[m], j[k]j\in[k], are i.i.d. copies of a normalized isotropic random vector yRn\mathbf{y}\in \mathbb{R}^n. For every fixed k1k\ge 1, if the Normalized Counting Measures of {τα}α\{\tau _{\alpha }\}_{\alpha} converge weakly as m,nm,n\rightarrow \infty, m/nkc[0,)m/n^k\rightarrow c\in \lbrack 0,\infty ) and y\mathbf{y} is a good vector in the sense of Definition 1.1, then the Normalized Counting Measures of eigenvalues of Mn,m,k(y)\mathcal{M}_{n,m,k}(\mathbf{y}) converge weakly in probability to a non-random limit found in [15]. For k=2k=2, we define a subclass of good vectors y\mathbf{y} for which the centered linear eigenvalue statistics n1/2Trφ(Mn,m,2(y))n^{-1/2}\text{Tr} \,\varphi(\mathcal{M}_{n,m,2}(\mathbf{y}))^\circ converge in distribution to a Gaussian random variable, i.e., the Central Limit Theorem is valid.

Keywords

Cite

@article{arxiv.1602.08613,
  title  = {CLT for linear eigenvalue statistics for a tensor product version of sample covariance matrices},
  author = {Anna Lytova},
  journal= {arXiv preprint arXiv:1602.08613},
  year   = {2017}
}
R2 v1 2026-06-22T12:59:11.366Z