{"type":"ScholarlyArticle","title":"Actively Learning Concepts and Conjunctive Queries under ELr-Ontologies","authors":[{"name":"Maurice Funk","slug":"maurice-funk","given":"Maurice","family":"Funk","affiliation":""},{"name":"Jean Christoph Jung","slug":"jean-christoph-jung","given":"Jean Christoph","family":"Jung","affiliation":""},{"name":"Carsten Lutz","slug":"carsten-lutz","given":"Carsten","family":"Lutz","affiliation":""}],"abstract":"We consider the problem to learn a concept or a query in the presence of an ontology formulated in the description logic ELr, in Angluin's framework of active learning that allows the learning algorithm to interactively query an oracle (such as a domain expert). We show that the following can be learned in polynomial time: (1) EL-concepts, (2) symmetry-free ELI-concepts, and (3) conjunctive queries (CQs) that are chordal, symmetry-free, and of bounded arity. In all cases, the learner can pose to the oracle membership queries based on ABoxes and equivalence queries that ask whether a given concept/query from the considered class is equivalent to the target. The restriction to bounded arity in (3) can be removed when we admit unrestricted CQs in equivalence queries. We also show that EL-concepts are not polynomial query learnable in the presence of ELI-ontologies.","doi":"10.24963/ijcai.2021/260","url":"https://ijcai.org/proceedings/2021/260","pdf":"https://ijcai.org/proceedings/2021/0260.pdf","markdown":"https://ijcai.org/proceedings/2021/260.md","bibtex":"https://ijcai.org/proceedings/2021/bibtex/260","volume":{"slug":"2021","title":"Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2021","url":"https://ijcai.org/proceedings/2021/","year":2021,"location":"Montreal","dates":"19-27 August 2021","editors":"Prof. Zhi-Hua Zhou","isbn":"978-0-9992411-9-6","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2021"},"section":"Knowledge Representation and Reasoning","track":"Main Track","number":260,"pages":{"first":1887,"last":1893},"keywords":["Knowledge Representation and Reasoning: Description Logics and Ontologies"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}