2009/11/16 by Olivier Ledoit, Sandrine Péché, Ledoit, Olivier +1 · 6 citations
Mathematics · #Advanced Combinatorial Mathematics #FOS: Mathematics #Probability (math.PR) #Random Matrices and Applications #Statistics Theory (math.ST) #Stochastic processes and statistical mechanics
paper · pdf · doi:10.48550/arxiv.0911.3010
openalex publication_date 2009/11/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider sample covariance matrices SN=(1)/(p)ΣN1/2XNXN^* ΣN1/2 where XN is a N × p real or complex matrix with i.i.d. entries with finite 12\rm th moment and ΣN is a N × N positive definite matrix. In addition we assume that the spectral measure of ΣN almost surely converges to some limiting probability distribution as N → ∞ and p/N → γ>0. We quantify the relationship between sample and population eigenvectors by studying the asymptotics of functionals of the type (1)/(N) Tr (g(ΣN) (SN-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.