On complex type hierarchy

Discusses the theoretical foundation for type hierarchy of complex objects to extend modelling concepts, semantics and constraints. Complex objects consist of entities and data-structure instances. We assume general constructions of data structures, i.e. not only sets and tuples but any structuring operators are allowed. Our discussion uses an instance-based data model. Since there may be infinite complex type information to each instance, we explore a simplified description in such a way that type schemes contain only least-general types. The heart of our approach exists in the semantic orders of complex objects.