An equivalent !-martingale measure (E!MM) for a given stochastic process Sis a probability measure R equivalent to the original measure P such that S isan R-!-martingale. Existence of an E!MM is equivalent to a classical absenceof-arbitrage property of S, and is invariant if we replace the...

We introduce a universal framework for mean-covariance robust risk measurement andportfolio optimization.We model uncertainty in terms of the Gelbrich distance on the mean-covariance space, along with prior structural information about the population distribution.Our approach is related to the...