1999 年 14 巻 6 号 p. 1019-1032
Building an ontology requires clear understanding of what can be concepts with what relations to other concepts. an ontology thus focuses on "objects" themselves rather than "representation" of them. However, few research have dealt with what to represent to date. Theory of content (what to represent) is badly needed. As a basis of ontological engineering, this paper presents ontological theories of semantic links such as is-a and part-of based on the set theory. Formulation of instance-of, is-a and part-of links is done based on member-of and subset-of relations sets. Concepts of relations and roles are also investigated to come up with a few guidelines of an ontology design. Although the research is not completed yet, basic design for an ontology representation language of solid foundation has been done.