2019/01/23 by Blanchet, Jose, Si, Nian
#FOS: Mathematics #Optimization and Control (math.OC) #Statistics Theory (math.ST)
paper · doi:10.48550/arxiv.1901.07693
In a recent paper, Nguyen, Kuhn, and Esfahani (2018) built a distributionally robust estimator for the precision matrix of the Gaussian distribution. The distributional uncertainty size is a key ingredient in the construction of this estimator. We develop a statistical theory which shows how to optimally choose the uncertainty size to minimize the associated Stein loss. Surprisingly, rather than the expected canonical square-root scaling rate, the optimal uncertainty size scales linearly with the sample size.