We study FO-rewritability of conjunctive queries in the presence of ontologies formulated in a description logic between EL and Horn-SHIF, along with related query containment problems. Apart from providing characterizations, we establish complexity results ranging from ExpTime via NExpTime to 2ExpTime, pointing out several interesting effects. In particular, FO-rewriting is more complex for conjunctive queries than for atomic queries when inverse roles are present, but not otherwise.
@article{arxiv.2011.09836,
title = {First Order-Rewritability and Containment of Conjunctive Queries in Horn Description Logics},
author = {Meghyn Bienvenu and Peter Hansen and Carsten Lutz and Frank Wolter},
journal= {arXiv preprint arXiv:2011.09836},
year = {2020}
}