Abstract : We discuss the parameterised complexity of answering tree-shaped ontology-mediated queries (OMQs) in OWL 2 QL under various restrictions on their ontologies and conjunctive queries (CQs). In particular, we construct an ontology T such that answering OMQs (T , q) with tree-shaped CQs q is W[1]-hard if the number of leaves in q is regarded as the parameter. The number of leaves has previously been identified as an important characteristic of CQs as bounding it leads to tractable OMQ answering. Our result shows that treating it as a parameter does not make the problem fixed-parameter tractable, even for a fixed ontology.
Type de document :
Communication dans un congrès
DL: Description Logics, Jul 2017, Montpellier, France. 30th International Workshop on Description Logics, CEUR Workshop Proceedings (1879), 2017
https://hal.inria.fr/hal-01632925
Contributeur : Meghyn Bienvenu
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Soumis le : vendredi 10 novembre 2017 - 17:27:57
Dernière modification le : mercredi 12 décembre 2018 - 14:01:09
Document(s) archivé(s) le : dimanche 11 février 2018 - 14:46:26
Meghyn Bienvenu, Stanislav Kikot, Roman Kontchakov, Vladislav Ryzhikov, Michael Zakharyaschev. On the Parameterised Complexity of Tree-Shaped Ontology-Mediated Queries in OWL 2 QL. DL: Description Logics, Jul 2017, Montpellier, France. 30th International Workshop on Description Logics, CEUR Workshop Proceedings (1879), 2017. 〈hal-01632925〉