ISO 13250 and the XTM specification cover the subjects of validation and consistency only slightly. The Conformance section of ISO 13250 focuses on the understanding of the defined constructs, the interchange syntax, and the import/export of topic maps.
Both the designer and the editor of topic maps need system support when designing and creating a map that will consist of millions of topics and associations. The question of the consistency of the map becomes a key issue because it is nearly impossible to check a map of that size manually. For that reason we need concepts to declare consistency constraints and to validate that those constraints have been obeyed [Rath 1999; Grønmo 2000].
Consequently, a separate schema ...