Rewriting Conjunctive Queries over Description Logic Knowledge Bases
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- Pérez-Urbina H., Motik B., Horrocks I. (2008) Rewriting Conjunctive Queries over Description Logic Knowledge Bases. In: Schewe KD., Thalheim B. (eds) Semantics in Data and Knowledge Bases. SDKB 2008. Lecture Notes in Computer Science, vol 4925. Springer, Berlin, Heidelberg
We consider the problems of conjunctive query answering and rewriting for information integration systems in which a Description Logic ontology is used to provide a global view of the data. We present a resolution-based query rewriting algorithm for DL-Lite + ontologies, and use it to show that query answering in this setting is NLogSpace-complete with respect to data complexity. We also show that our algorithm produces an optimal rewriting when the input ontology is expressed in the language DL-Lite. Finally, we sketch an extended version of the algorithm that would, we are confident, be optimal for several DL languages with data complexity of query answering ranging from LogSpace to PTime-complete.
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