Relating practical representations of imprecise probabilities

There exist many practical representations of prob-ability families that make them easier to handle. Among them are random sets, possibility distribu-tions, probability intervals, Ferson's p-boxes and Neu-maier's clouds. Both for theoretical and practical con-siderations, it is important to know whether one rep-resentation has the same expressive power than other ones, or can be approximated by other ones. In this paper, we mainly study the relationships between the two latter representations and the three other ones