Behind the inheritance relations in a semantic network

摘要

There are many confused meanings on the use of ISA (is-a), AKO (a-kind-of), and ISPART (is-part-of) relations. This problem can be solved only by defining the precise meaning of the ISA, AKO and ISPART relations, and by recognizing either a class node or an object node for a given node in a semantic network. The author makes clear, precise and consistent definitions for these inheritance relations based on the two fundamental types of information that these relations are intended to represent: classes and objects. The features explored from these relations explain the use of these three relations and what properties each has. By dividing the properties related by ISA, AKO and ISPART relations into property values and property attributes, it is found that a property value relates to a specific class or object only and is not an inheritable property, while a property attribute corresponds to the universal quantification in predicate logic and is inheritable by the descendants of a class or object.