The modular structure of an ontology: atomic decomposition

Extracting a subset of a given ontology that cap-tures all the ontology’s knowledge about a specified set of terms is a well-understood task. This task can be based, for instance, on locality-based mod-ules. However, a single module does not allow us to understand neither topicality, connectedness, struc-ture, or superfluous parts of an ontology, nor agree-ment between actual and intended modeling. The strong logical properties of locality-based modules suggest that the family of all such mod-ules of an ontology can support comprehension of the ontology as a whole. However, extracting that family is not feasible, since the number of locality-based modules of an ontology can be exponential w.r.t. its size. In this paper we report on a new approach that en-ables us to efficiently extract a polynomial repres-entation of the family of all locality-based modules of an ontology. We also describe the fundamental algorithm to pursue this task, and report on experi-ments carried out and results obtained.