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Query inseparability for \(ALC\) ontologies

Botoeva, Elena, Lutz, Carsten, Ryzhikov, Vladislav, Wolter, Frank, Zakharyaschev, Michael (2019) Query inseparability for \(ALC\) ontologies. Artificial Intelligence, 272 . pp. 1-51. ISSN 0004-3702. (doi:10.1016/j.artint.2018.09.003) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:90808)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
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We investigate the problem whether two \(ALC\) ontologies are indistinguishable (or inseparable) by means of queries in a given signature, which is fundamental for ontology engineering tasks such as ontology versioning, modularisation, update, and forgetting. We consider both knowledge base (KB) and TBox inseparability. For KBs, we give model-theoretic criteria in terms of (finite partial) homomorphisms and products and prove that this problem is undecidable for conjunctive queries (CQs), but 2ExpTime-complete for unions of CQs (UCQs). The same results hold if (U)CQs are replaced by rooted (U)CQs, where every variable is connected to an answer variable. We also show that inseparability by CQs is still undecidable if one KB is given in the lightweight DL \(EL\) and if no restrictions are imposed on the signature of the CQs. We also consider the problem whether two \(ALC\) TBoxes give the same answers to any query over any ABox in a given signature and show that, for CQs, this problem is undecidable, too. We then develop model-theoretic criteria for Horn \(ALC\) TBoxes and show using tree automata that, in contrast, inseparability becomes decidable and 2ExpTime-complete, even ExpTime-complete when restricted to (unions of) rooted CQs.

Item Type: Article
DOI/Identification number: 10.1016/j.artint.2018.09.003
Uncontrolled keywords: Description logic; Knowledge base; Conjunctive query; Query inseparability; Computational complexity; Tree automaton
Subjects: Q Science > QA Mathematics (inc Computing science) > QA 76 Software, computer programming, > QA76.9.H85 Human computer interaction
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Computing
Depositing User: Amy Boaler
Date Deposited: 12 Oct 2021 08:34 UTC
Last Modified: 13 Oct 2021 10:04 UTC
Resource URI: (The current URI for this page, for reference purposes)
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