Answering regular path queries mediated by unrestricted SQ ontologies

Gutierrez Basulto, Victor ORCID: https://orcid.org/0000-0002-6117-5459, Ibanez Garcia, Yazmin ORCID: https://orcid.org/0000-0002-1276-904X, Jung, Jean Christoph and Murlak, Filip 2023. Answering regular path queries mediated by unrestricted SQ ontologies. Artificial Intelligence 314 , 103808. 10.1016/j.artint.2022.103808

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Abstract

A prime application of description logics is ontology-mediated query answering, with the query language often reaching far beyond instance queries. Here, we investigate this task for positive existential two-way regular path queries and ontologies formulated in the expressive description logic , where denotes the extension of the basic description logic with transitive roles () and qualified number restrictions () which can be unrestrictedly applied to both non-transitive and transitive roles (). Notably, the latter is usually forbidden in expressive description logics. As the main contribution, we show decidability of ontology-mediated query answering in that setting and establish tight complexity bounds, namely 2ExpTime-completeness in combined complexity and coNP-completeness in data complexity. Since the lower bounds are inherited from the fragment , we concentrate on providing upper bounds. As main technical tools we establish a tree-like countermodel property and a characterization of when a query is not satisfied in a tree-like interpretation. Together, these results allow us to use an automata-based approach to query answering.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Computer Science & Informatics
Publisher:	Elsevier
ISSN:	0004-3702
Date of First Compliant Deposit:	17 November 2022
Date of Acceptance:	16 October 2022
Last Modified:	03 May 2023 19:36
URI:	https://orca.cardiff.ac.uk/id/eprint/154289

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