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arXiv 0911.3010math.PRmath.STstat.TH
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某些大样本协方差阵系综的特征向量

Eigenvectors of some large sample covariance matrix ensembles

Olivier Ledoit, Sandrine Péché

摘要:

我们考虑样本协方差矩阵$S_N=\frac{1}{p}Σ_N^{1/2}X_NX_N^* Σ_N^{1/2}$,其中$X_N$是具有i.i.d.的$N \times p$实数或复数矩阵。元素具有有限的$12^{\rm th}$矩,并且$Σ_N$是$N \times N$正定矩阵。此外,我们还假设$Σ_N$的谱测度几乎必然收敛于某个极限概率分布,如$N \to \infty$和$p/N \to γ>0.$。我们通过研究$\frac{1}{N} \text{Tr} (g(Σ_N) (S_N-zI)^{-1})),$型泛函的渐近性来量化样本和总体特征向量之间的关系,其中$I$是单位矩阵,$g$是有界函数,$z$是复数。然后,这是用来计算样本特征值的渐近最优偏差校正,铺平了道路,新一代的协方差矩阵及其逆的改进估计。

英文摘要:

We consider sample covariance matrices $S_N=\frac{1}{p}Σ_N^{1/2}X_NX_N^* Σ_N^{1/2}$ where $X_N$ is a $N \times p$ real or complex matrix with i.i.d. entries with finite $12^{\rm th}$ moment and $Σ_N$ is a $N \times N$ positive definite matrix. In addition we assume that the spectral measure of $Σ_N$ almost surely converges to some limiting probability distribution as $N \to \infty$ and $p/N \to γ>0.$ We quantify the relationship between sample and population eigenvectors by studying the asymptotics of functionals of the type $\frac{1}{N} \text{Tr} (g(Σ_N) (S_N-zI)^{-1})),$ where $I$ is the identity matrix, $g$ is a bounded function and $z$ is a complex number. This is then used to compute the asymptotically optimal bias correction for sample eigenvalues, paving the way for a new generation of improved estimators of the covariance matrix and its inverse.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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