There is significant parallelism between several hierarchies in the ontology. Recognizing these parallel structures not only guides one's navigation through the ontology but also helps one understand the relations that form the cross links between these hierarchies. The most visible parallelism in structure is between the set of three hierarchies in the social world: SOCIAL-ROLE, WORK-ACTIVITY, and FIELD-OF-STUDY. Some of these three hierarchies are also in parallel with other SOCIAL-OBJECT and SOCIAL-EVENT structures. Figure 14 illustrates the cross-links between these parallel hierarchies.
Figure 14:
Parallel Hierarchies and Cross Links in the Ontology.
Kavi Mahesh