On the Semantics of Linking and Importing in Modular Ontologies

Modular ontology languages, such as Distributed Description Logics (DDL), E-connections and Package-based Description Logics (P-DL) offer two broad classes of approaches to connect multiple ontology modules: the use of mappings or linkings between ontology modules e.g., DDL and E-connections; and the use of importing e.g., P-DL. The major difference between the two approaches is on the usage of “foreign terms” at the syntactic level, and on the local model disjointness at the semantic level. We compare the semantics of linking in DDL and E-connections, and importing in P-DL within the Distributed First Order Logics (DFOL) framework. Our investigation shows that the domain disjointness assumption adopted by the linking approach leads to several semantic difficulties. We explore the possibility of avoiding some of these difficulties using the importing approach to linking ontology modules.