{"type":"ScholarlyArticle","title":"Query Answering in Description Logics with Transitive Roles","authors":[{"name":"Thomas Eiter","slug":"thomas-eiter","given":"Thomas","family":"Eiter","affiliation":""},{"name":"Carsten Lutz","slug":"carsten-lutz","given":"Carsten","family":"Lutz","affiliation":""},{"name":"Magdalena Ortiz","slug":"magdalena-ortiz","given":"Magdalena","family":"Ortiz","affiliation":""},{"name":"Mantas Simkus","slug":"mantas-simkus","given":"Mantas","family":"Simkus","affiliation":""}],"abstract":"We study the computational complexity of conjunctive query answering w.r.t. ontologies formulated in fragments of the description logic SHIQ. Our main result is the identification of two new sources of complexity: the combination of transitive roles and role hierarchies which results in 2ExpTime-hardness, and transitive roles alone which result in coNExpTime-hardness. These bounds complement the existing result that inverse roles make query answering in SHIQ 2ExpTime-hard. We also show that conjunctive query answering with transitive roles, but without inverse roles and role hierarchies, remains in ExpTime if the ABox is tree-shaped.Thomas Eiter, Carsten Lutz, Magdalena Ortiz, Mantas Simkus","doi":null,"url":"https://ijcai.org/proceedings/2009/131","pdf":"https://ijcai.org/proceedings/2009/0131.pdf","markdown":"https://ijcai.org/proceedings/2009/131.md","bibtex":"https://ijcai.org/proceedings/2009/bibtex/131","volume":{"slug":"2009","title":"Proceedings of the Twenty-First International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2009","url":"https://ijcai.org/proceedings/2009/","year":2009,"location":"Pasadena, California, USA","dates":"","editors":"Hiroaki Kitano","isbn":"","publisher":"International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":null,"track":"","number":131,"pages":{"first":759,"last":763},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}