Types, structures and theories in NKI

Abstract

The National Knowledge Infrastructure (NKI) is a multi-domain knowledge base. The classical type theory is no longer appropriate to describe every kind of object in multi-domains, such as artifacts, natural or micro objects. Three different kinds of type theories are defined: the classical, atomic and pseudo type theories; in the classical type theory, two new type constructors are defined: setm and ∨, to describe the types of sets of all the elements of the types and unions of two sets of different types, respectively. The structures and categories in the type theory are defined, and the sub-structures and homomorphic structures are used to describe the part-of relations that give the algebraic specifications for the natural objects and the part-of relations between the natural objects, micro objects and artifacts.