Basic theories of ontology

The spectrum of ontology research spreads from account of existence in the world by philosophers to building models of concrete targets by computer scientists. In spite of its wide spectrum, each enterprise needs firm and sound basic theories such as mereotopology, theory of identity, and theory of dependence. All the three theories collectively provide us with guidlines in building concrete ontologies of interest and in investigation of definitions and operation of basic semantic links such as is-a, part-of, instance-of. Thus, the three theories play important roles not only in the basic research but in application settings.

We are currently involved in establishing an ontological semantic theory of semantic links. The following are the current topics of interest:

1. What is the difference between instance-of and member-of links(a class and a set)?
2. What is the difference between is-a and part-of links?
3. What is the difference between meta-object and super-sub relations(instance-of and is-a)?
4. How many types of part-of links do we need?
5. What is an instance of a relation?
6. Can't the concept of "husband" have an instance?

Major publications:

1. Foundation of Ontological Engineering--An ontological theory of semantic links, classes, relations and roles--(in Japanese), AI Technical Report 99-03, I.S.I.R., Osaka University, March, 1999