The Logic of Inheritance in Frame Systems

Abstract

This paper shows how the semantics of frames with exceptions can be described logically. We define a simple (purely declarative) frame language allowing for multiple inheritance and meta classes (i.e. the instances of a class may be classes themselves). Expressions of this language are translated into first order formulas. Circumscription of a certain predicate in the resulting theory yields the desired semantics. Our approach allows the intuition that subclasses should override superclasses to be represented in a very natural way. Inheritance systems have a long tradition in AI. They allow the description of hierarchies of objects and