I review some applications of random matrix theory to multivariate statistics. Suppose one is interested in the covariance matrix of a random vector whose distribution is unknown. In order to determine the covariances from empirical observations, one approximates them using empirical averages obtained from a series of measurements. The resulting sample covariance matrix is random, and its relationship with the true covariance matrix rather intricate. I outline some recent progress in understanding the behaviour of sample covariance matrices. The cornerstone of the proofs is an anisotropic local law for the resolvent. Applications include the Tracy-Widom distribution of eigenvalues near the spectral edges.
When? | 07.10.2014 17:15 |
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Where? | PER 08 Phys 2.52 Chemin du Musée 3, 1700 Fribourg |
Contact | Department of Mathematics isabella.schmutz@unifr.ch |