We examine the estimation problem for shape-restricted functions that are continuous, non-negative, monotone non-decreasing, and strictly concave. A sieve estimator based on bivariate Bernstein polynomials is proposed. This estimator is drawn from a sieve, a set of shape-restricted Bernstein...

The multidimensional stock control that functions in a random Markov environment is considered. The mathematical formalization of this model was considered with the use of sums of the random variables defined on the Markov chains. The authors introduce a definition of risk function of the type...