Prolog Based Description Logic Reasoning

In this paper we present the recent developments of the DLog system, an ABox reasoning engine for the the $\mathcal{SHIQ}$ description logic language. DLog differs from traditional description logic reasoners in that it transforms description logic axioms into a Prolog program. The transformation is done independently from the ABox, i.e. the set of assertions about the individuals. This makes it possible to store the ABox assertions in a database, rather than in memory. This approach results in better scalability and helps using description logic ontologies directly on top of existing information sources. The transformation involves several optimisation steps, which aim at producing more efficient Prolog programs. In this paper we focus on the partial evaluation technique we apply to obtain programs that do not use logic variables. This simplifies the implementation, improves performance and opens up the possibility of compiling into Mercury code. In the paper we also present the recent architectural changes in the DLog system, summarise the most important features of the implementation and evaluate the performance of DLog by comparing it to the best available description logic reasoners.