A probabilistic approach to ordering formulas in a possibilistic knowledge base
Résumé
In this paper, a careful analysis of interval-iralued possibilistic knowledge bases indicates that there eidsts a natural. probability distribution over the set of orderings of formulae compatible with the weights given in the knowledge base. We propose a new view, by which a possibilistic knowledge base can be considered in term of such probability distribution. It reveals some interconnections between probabilistic and possibilistic logics. We show that the principle of minimum specificity, widely used in possibilistic logic, is a special case of the principle of maximum likehood (at least, from the standpoint of nonmonotonic reasoning) . We propose a formula to calculate probability for a defeasible conclusion. Moreover, the proposed view seems to be useful for other practical purposes. As an example, we apply it to a traditional problem of fusion of possibilistic knowledge from many sources and derive a new solution.