2019/11/26 by Heng Zhang, Yan Zhang, Zhang, Heng +7
Computer Science · #Advanced Database Systems and Queries #Artificial Intelligence (cs.AI) #Databases (cs.DB) #FOS: Computer and information sciences #Logic in Computer Science (cs.LO) #Semantic Web and Ontologies #Service-Oriented Architecture and Web Services
paper · pdf · doi:10.48550/arxiv.1911.11359
openalex publication_date 2019/11/26 · openalex created_date 2019/12/05 · openalex updated_date 2026/07/28
An ontology language for ontology mediated query answering (OMQA-language) is universal for a family of OMQA-languages if it is the most expressive one among this family. In this paper, we focus on three families of tractable OMQA-languages, including first-order rewritable languages and languages whose data complexity of the query answering is in AC0 or PTIME. On the negative side, we prove that there is, in general, no universal language for each of these families of languages. On the positive side, we propose a novel property, the locality, to approximate the first-order rewritability, and show that there exists a language of disjunctive embedded dependencies that is universal for the family of OMQA-languages with locality. All of these results apply to OMQA with query languages such as conjunctive queries, unions of conjunctive queries and acyclic conjunctive queries.