DEFAULT LOGICS: A UNIFIED VIEW

Christine Froidevaux, Jérôme Mengin
1994 Computational intelligence  
Default logic has been introduced for handling reasoning with incomplete knowledge. It has been widely studied, and various definitions have been proposed for it. Most of the variants have been defined by means of fixed points of some operator. We propose here another approach, which is based on a study of the way in which general rules with exceptions, used in a default reasoning process, can contradict one another. We then isolate sets of non-contradicting rules, as large as possible in order
more » ... to exploit as much information as possible, and construct, for each of these sets of rules, the set of conclusions that can be deduced from it. We show that our framework encompasses most of the existing variants of default logic, allowing those variants to be compared from a knowledge representation point of view. Our approach also enables us to provide an operational definition of extensions in some interesting cases. Proof theoretical and semantical aspects are investigated.
doi:10.1111/j.1467-8640.1994.tb00168.x fatcat:p2sqvsrwhbcytbm5qqvmzuzcdu