Gerasimova, Olga, Kikot, Stanislav, Kurucz, Agi, Podolskii, Vladimir and Zakharyaschev, Michael (2020) A data complexity and rewritability tetrachotomy of ontology-mediated queries with a covering axiom. Technical Report. International Joint Conferences on Artificial Intelligence Organization.
Aiming to understand the data complexity of answering conjunctive queries mediated by an axiom stating that a class is covered by the union of two other classes, we show that deciding their first-order rewritability is PSPACE-hard and obtain a number of sufficient conditions for membership in AC0, L, NL, and P. Our main result is a complete syntactic AC0/NL/P/CONP tetrachotomy of path queries under the assumption that the covering classes are disjoint.
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