Sanity-Checking Multiple Levels of Classification - A Formal Approach with a ConceptBase Implementation.

Multiple levels of classification naturally occur in many domains. Several multi-level modeling approaches account for this and a subset of them attempt to provide their users with sanity-checking mechanisms in order to guard them against conceptually ill-formed models. Historically, the respective multi-level well-formedness schemes have either been overly restrictive or too lax. Orthogonal Ontological Classification has been proposed as a foundation that combines the selectivity of strict schemes with the flexibility afforded by laxer schemes. In this paper, we present a formalization of Orthogonal Ontological Classification, which we empirically validated to demonstrate some of its hitherto only postulated claims using an implementation in ConceptBase. We discuss both the formalization and the implementation, and report on the limitations we encountered.