terms . Krypton : A Functional Approach to Knowledge Representation

The widespread appeal of frame taxonomies seems due to how closely they match our intuitions about how to structure the world (as illustrated in folk taxonomies, for example). They also suggest enticing directions for processing (inheritance, defaults, etc.) and have found applications in other areas of computer science, such as database management and object-oriented programming. While the basic ideas of frame systems are straightforward, complications arise in their design and use. These difficulties typically arise because (1) structures are interpreted in different ways at different times (the principal ambiguity being between definitional and factual interpretations) and (2) the meaning of the representation language is specified only in terms of the data structures used to implement it (typically inheritance networks). We have developed a design strategy for avoiding these types of problems and have implemented a representation system based on it. The system, called Krypton, clearly distinguishes between definitional and factual information. In particular, Krypton has two representation languages, one for forming descriptive terms and one for making statements about the world using these terms. Further, Krypton provides a functional view of a knowledge base, characterized in terms of what it can be asked or told, not in terms of the particular structures it uses to represent knowledge.