{"type":"ScholarlyArticle","title":"Tractable Concept Languages","authors":[{"name":"Francesco M. Donini","slug":"francesco-m-donini","given":"Francesco M.","family":"Donini","affiliation":""},{"name":"Maurizio Lenzerini","slug":"maurizio-lenzerini","given":"Maurizio","family":"Lenzerini","affiliation":""},{"name":"Daniele Nardi","slug":"daniele-nardi","given":"Daniele","family":"Nardi","affiliation":""},{"name":"Werner Nutt","slug":"werner-nutt","given":"Werner","family":"Nutt","affiliation":""}],"abstract":"We present two concept languages, called PC1 and PC2, which are extensions of :Fe-. We prove that the subsumption problem in these languages can be solved in polynomial time. Both languages include a construct for expressing inverse roles, which has not been considered up to now in tractable languages. In addition, P C1 includes number restrictions and negation of primitive concepts, while P C2 includes role conjunction and role chaining. By exploiting recent complexity results, we show that none of the constructs usually considered in concept languages can be add ed toP C 1 and P C2 without losing tractability. Therefore, on the assumption that languages are characterized by the set of constructs they provide, the two languages presented in this paper provide a solution to the problem of singling out an optimal trade-off between expressive power and computational complexity.","doi":null,"url":"https://ijcai.org/proceedings/1991/69","pdf":"https://ijcai.org/proceedings/1991/0069.pdf","markdown":"https://ijcai.org/proceedings/1991/69.md","bibtex":"https://ijcai.org/proceedings/1991/bibtex/69","volume":{"slug":"1991","title":"Proceedings of the Twelfth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 1991","url":"https://ijcai.org/proceedings/1991/","year":1991,"location":"Sydney, New South Wales, Australia","dates":"24-30 August 1991","editors":"John Mylopoulos and Ray Reiter","isbn":"","publisher":"International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":"Knowledge Representation","track":"Knowledge Representation","number":69,"pages":{"first":458,"last":464},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}