Extending Decidable Existential Rules by Joining Acyclicity and Guardedness
Markus Krötzsch, Sebastian Rudolph
Extending Decidable Existential Rules by Joining Acyclicity and Guardedness
Abstract. Existential rules, i.e. Datalog extended with existential quantifiers in rule heads, are currently studied under a variety of names such as Datalog+/–, ∀∃-rules, and tuple-generating dependencies. The renewed interest in this formalism is fuelled by a wealth of recently discovered language fragments for which query answering is decidable. This paper extends and consolidates two of the main approaches in this field – acyclicity and guardedness – by providing (1) complexity-preserving generalisations of weakly acyclic and weakly (frontier-)guarded rules, and (2) a novel formalism of glut-(frontier-)guarded rules that subsumes both. This builds on an insight that acyclicity can be used to extend any existential rule language while retaining decidability. Besides decidability, combined query complexities are established in all cases.
Published at IJCAI2011 (Conference paper)
Download PDF (last update: Apr 14 2011)
Citation details
- Markus Krötzsch, Sebastian Rudolph. Extending Decidable Existential Rules by Joining Acyclicity and Guardedness. In Proceedings of the 22nd International Joint Conference on Artificial Intelligence (IJCAI-11), pp. 963–968. IJCAIProperty "Publisher" has a restricted application area and cannot be used as annotation property by a user. 2011.
author = {Markus Kr{\"o}tzsch and Sebastian Rudolph},
title = {Extending Decidable Existential Rules by
Joining Acyclicity and Guardedness},
editor = {Toby Walsh},
booktitle= {Proceedings of the 22nd International Joint
Conference on Artificial Intelligence (IJCAI'11)},
year = {2011},
publisher= {AAAI Press/IJCAI},
pages = {963--968}
}
Remarks
This paper is based on the AIFB technical report Revisiting Acyclicity and Guardedness Criteria for Decidability of Existential Rules where full proofs can be found.
