Tractable Reasoning with DL-Programs over Datalog-rewritable Description Logics

The deployment of KR formalisms to the Web has created the need for formalisms that combine heterogeneous knowledge bases. Nonmonotonic dl-programs provide a loose integration of Description Logic (DL) ontologies and Logic Programming (LP) rules with negation, where a rule engine can query an ontology with a native DL reasoner. However, even for tractable dl-programs, the overhead of an external DL reasoner might be considerable. To remedy this, we consider Datalog-rewritable DL ontologies, i.e., ones that can be rewritten to Datalog programs, such that dl-programs can be reduced to Datalog¬, i.e, Datalog with negation, under well-founded semantics. To illustrate this framework, we consider several Datalog-rewritable DLs. Besides fragments of the tractable OWL 2 Profiles, we also present ℒ𝒟ℒ+as an interesting DL that is tractable while it has some expressive constructs. Our results enable the usage of DBLP technology to reason efficiently with dl-programs in presence of negation and recursion, as a basis for advanced applications.