{"type":"ScholarlyArticle","title":"EQL-Lite: Effective First-Order Query Processing in Description Logics","authors":[{"name":"Diego Calvanese","slug":"diego-calvanese","given":"Diego","family":"Calvanese","affiliation":""},{"name":"Giuseppe De Giacomo","slug":"giuseppe-de-giacomo","given":"Giuseppe","family":"De Giacomo","affiliation":""},{"name":"Domenico Lembo","slug":"domenico-lembo","given":"Domenico","family":"Lembo","affiliation":""},{"name":"Maurizio Lenzerini","slug":"maurizio-lenzerini","given":"Maurizio","family":"Lenzerini","affiliation":""},{"name":"Riccardo Rosati","slug":"riccardo-rosati","given":"Riccardo","family":"Rosati","affiliation":""}],"abstract":"Querying Description Logic knowledge bases has received great attention in the last years. In such a problem, the need of coping with incomplete information is the distinguishing feature with respect to querying databases. Due to this feature, we have to deal with two conflicting needs: on the one hand, we would like to query the knowledge base with sophisticated mechanisms provided by full first-order logic (FOL); on the other hand, the presence of incomplete information makes query answering a much more difficult task than in databases. In this paper we advocate the use of a nonmonotonic epistemic FOL query language as a means for expressing sophisticated queries over Description Logic knowledge bases. We show that through a controlled use of the epistemic operator, resulting in the language called EQL-Lite, we are able to formulate full FOL queries over Description Logic knowledge bases, while keeping computational complexity of query answering under control. In particular, we show that EQL-Lite queries over DL-Lite knowledge bases are FOL reducible (i.e., compilable into SQL) and hence can be answered in LOGSPACE through standard database technologies.","doi":null,"url":"https://ijcai.org/proceedings/2007/42","pdf":"https://ijcai.org/proceedings/2007/0042.pdf","markdown":"https://ijcai.org/proceedings/2007/42.md","bibtex":"https://ijcai.org/proceedings/2007/bibtex/42","volume":{"slug":"2007","title":"Proceedings of the Twentieth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2007","url":"https://ijcai.org/proceedings/2007/","year":2007,"location":"Hyderabad, India","dates":"","editors":"Ramon López de Mántaras","isbn":"","publisher":"International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":null,"track":"","number":42,"pages":{"first":274,"last":278},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}