Data Complexity of Query Answering in Description Logics

Diego Calvanese, Giuseppe De Giacomo, Domenico Lembo, Maurizio Lenzerini, and Riccardo Rosati

Proc. of the 10th Int. Conf. on the Principles of Knowledge Representation and Reasoning (KR 2006). 2006.

In this paper we study data complexity of answering conjunctive queries over Description Logic knowledge bases constituted by an ABox and a TBox. In particular, we are interested in characterizing the FOL-reducibility and the polynomial tractability boundaries of conjunctive query answering, depending on the expressive power of the DL used to express the knowledge base. FOL-reducibility means that query answering can be reduced to evaluating queries over the database corresponding to the ABox. Since first-order queries can be expressed in SQL, the importance of FOL-reducibility is that, when query answering enjoys this property, we can take advantage of Data Base Management System (DBMS) techniques for both representing data, i.e., ABox assertions, and answering queries via reformulation into SQL. What emerges from our complexity analysis is that the Description Logics of the DL-Lite family are the maximal logics allowing conjunctive query answering through standard database technology. In this sense, they are the first Description Logics specifically tailored for effective query answering over very large ABoxes.


@inproceedings{KR-2006,
   title = "Data Complexity of Query Answering in Description Logics",
   year = "2006",
   author = "Diego Calvanese and De Giacomo, Giuseppe and Domenico
Lembo and Maurizio Lenzerini and Riccardo Rosati",
   booktitle = "Proc. of the 10th Int. Conf. on the Principles of Knowledge
Representation and Reasoning (KR 2006)",
   pages = "260-270",
}
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