An Evidence-based Framework for a Theory of Inheritance

We present an approach to formalizing nonmonotonic multiple inheritance networks by combining concepts from logic programming and multi-valued logics in a uniform framework. A Horn-clause logic language is used for specifying inheritance networks. This allows a natural representation of class-subclass hierarchies and ambiguous inheritance networks. It also provides means for resolving ambiguities resulting from the network topology, but which are not inherent to the problem. We provide a model theory for the language and show how a unique intended model can be associated with every inheritance network. This model resembles the unique extension obtained in the skeptical theory of inheritance [Hor-87], but is more general. Finally, we present an algorithm which realizes the aforementioned semantics.