Capturing Homomorphism-Closed Decidable Queries with Existential Rules (Extended Abstract)
Camille Bourgaux, David Carral, Markus Krötzsch, Sebastian Rudolph, Michaël Thomazo
Abstract
Existential rules are a very popular ontology-mediated query language for which the chase represents a generic computational approach for query answering. It is straightforward that existential rule queries exhibiting chase termination are decidable and can only recognize properties that are preserved under homomorphisms. This paper is an extended abstract of our eponymous publication at KR 2021 where we show the converse: every decidable query that is closed under homomorphism can be expressed by an existential rule set for which the standard chase universally terminates. Membership in this fragment is not decidable, but we show via a diagonalisation argument that this is unavoidable.
BibTeX
@inproceedings{ijcai2022p733,
title = {Capturing Homomorphism-Closed Decidable Queries with Existential Rules (Extended Abstract)},
author = {Bourgaux, Camille and Carral, David and Krötzsch, Markus and Rudolph, Sebastian and Thomazo, Michaël},
booktitle = {Proceedings of the Thirty-First International Joint Conference on
Artificial Intelligence, {IJCAI-22}},
publisher = {International Joint Conferences on Artificial Intelligence Organization},
editor = {Lud De Raedt},
pages = {5269--5273},
year = {2022},
month = {7},
note = {Sister Conferences Best Papers},
doi = {10.24963/ijcai.2022/733},
url = {https://doi.org/10.24963/ijcai.2022/733},
}