Optimal estimation of functionals of high-dimensional mean and covariance matrix
高维均值与协方差矩阵泛函的最优估计
Motivated by portfolio allocation and linear discriminant analysis, we consider estimating a functional $\mathbfμ^T \mathbfΣ^{-1} \mathbfμ$ involving both the mean vector $\mathbfμ$ and covariance matrix $\mathbfΣ$. We study the minimax estimation of the functional in the high-dimensional setting where $\mathbfΣ^{-1} \mathbfμ$ is sparse. Akin to past works on functional estimation, we show that the optimal rate for estimating the functional undergoes a phase transition…