In this paper, we reconsider the irreversibility theory in an non-Bayesian framework. First, we propose three definitions in order to make the difference between the effects of the irreversibilities and of the information which were mixed in the standard definition of the "irreversibility...

We show, in the Choquet expected utility model, that preference for diversification, that is, convex preferences, is equivalent to a concave utility index and a convex capacity. We then introduce a weaker notion of diversification, namely ``sure diversification.'' We show that this implies that...