Class queries cannot be answered by a subtype. Subtype class schemas cannot be modified at run time. Subtypes do not allow for exceptions. Subclasses are not bound by implicit relationship types. The primary purpose of inheritance is the management of complexity.
Inheritance can be single or multiple, and full or partial.
Class schema changes must also be supported. Inheritance usually implies a sharing of a property, not a copy. Module and Agent Communication Information must be packaged and unpackaged for transmission and should require a minimum programmer effort to send and receive information. The transmission of information involves network connections and agent naming. Geometric Relationships and Topologies Specialized and efficient representations are used for geometric relationship computations.