Optimal Unbiased Estimation for Maximal Distribution
  Unbiased estimation for parameters of maximal distribution is a very fundamental problem in the statistical theory of sublinear expectation. In this paper, we proved that the maximum estimator is the largest unbiased estimator for the upper mean and the minimum estimator is the smallest unbiased estimator the the lower mean. 
Hanqing Jin and Shige Peng
math.PR