F-Logic#: Loosely Coupling F-Logic Rules and Ontologies

In W3C´s Rule Interchange Format (RIF), F-Logic rules have received considerable attention as a major logical rule formalism, while combinations of rules with Description Logic (DL) ontologies in RIF, let alone with F-Logic rules, are far less developed. To mend this, we first present F-Logic# knowledge bases, a framework based on the semantics of the well-investigated dl-programs, that provides a loose coupling approach to integrating F-Logic rules and DL ontologies by allowing rules to query the ontology using external atoms. We investigate the semantical properties of this framework and define a stratified fragment that allows for fast reasoning - a necessity on a Web with large amounts of data. We then shape F-Logic# as a RIF dialect, setting it firmly in a Web context and providing an expressive combination of F-Logic rules with DL ontologies in RIF. Finally, we show how to extend the F-Logic rule engine OntoBroker towards reasoning with F-Logic#, enabling as such a first commercial implementation for loosely-coupled ontologies and rules.