Lassoing Eigenvalues

Abstract

The properties of penalized sample covariance matrices depend on the choice of the penalty function. In this paper, we introduce a class of non-smooth penalty functions for the sample covariance matrix, and demonstrate how this method results in a grouping of the estimated eigenvalues. We refer to this method as "lassoing eigenvalues" or as the "elasso".

18 pages, 6 figures