Adding datatypes to ontology-mediated queries (OMQs) often makes query answering hard. As a consequence, the use of datatypes in OWL 2 QL has been severely restricted. In this paper we propose a new, non-uniform, way of analyzing the data-complexity of OMQ answering with datatypes. Instead of restricting the ontology language we aim at a classification of the patterns of datatype atoms in OMQs into those that can occur in non-tractable OMQs and those that only occur in tractable OMQs. To this end we establish a close link between OMQ answering with datatypes and constraint satisfaction problems over the datatypes. In a case study we apply this link to prove a P/coNP-dichotomy for OMQs over DL-Lite extended with the datatype (Q, ≤). The proof employs a recent dichotomy result by Bodirsky and Kára for temporal constraint satisfaction problems.
CITATION STYLE
Hernich, A., Lemos, J., & Wolter, F. (2017). Query answering in DL-Lite with datatypes: A non-uniform approach. In 31st AAAI Conference on Artificial Intelligence, AAAI 2017 (pp. 1142–1148). AAAI press. https://doi.org/10.1609/aaai.v31i1.10689
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