Classical and weighted knowledgebase transformations

In this paper, there is a review of some knowledgebase change operators, namely the revision, update, (symmetrical) model-fitting well known in the propositional case and some new problems concerning them. There is an extended set of axioms to avoid a certain problem in connection with revision. Based on the propositional case, we give some generalization of revision for first-order case. Furthermore we define an extension of the propositional knowledgebase to weighted knowledgebase. Finally we deal with the weighted knowledgebase transformations.