The Stam region, or the differential entropy region for sums of independent random vectors
Define the Stam region as the subset of the positive orthant in R^{2N−1} that arises from considering entropy powers of subset sums of N independent random vectors taking values in some Euclidean space. It is shown that the fractionally superadditive set functions give an outer bound for the Stam region, but that the supermodular set functions do not. In addition, various structural properties of the Stam region are explored.