Modular Ontologies - A Formal Investigation of Semantics and Expressivity

With the growing interest in modular ontology languages to address the need for collaborative development, integration, and use of ontologies on the Web, there is an urgent need for a common framework for comparing modular ontology language proposals on the basis of criteria such as their semantic soundness and expressive power. We introduce an Abstract Modular Ontology (AMO) language and offer precise definitions of semantic soundness such as localized semantics and exact reasoning, and expressivity requirements for modular ontology languages. We compare Distributed Description Logics (DDL), E-connections, and Package-Based Description Logics (P-DL) with respect to these criteria. Our analysis suggests that by relaxing the strong domain disjointedness assumption adopted in DDL and E-connection, as P-DL demonstrated, it is possible to overcome some known semantic difficulties and expressivity limitations of DDL and E-Connections.