A Proof Procedure for Data Dependencies
Journal of the ACM (JACM)
Conceptual structures: information processing in mind and machine
Conceptual structures: information processing in mind and machine
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Sound and Complete Forward and backward Chainingd of Graph Rules
ICCS '96 Proceedings of the 4th International Conference on Conceptual Structures: Knowledge Representation as Interlingua
Tractable Reasoning and Efficient Query Answering in Description Logics: The DL-Lite Family
Journal of Automated Reasoning
Graph-based Knowledge Representation: Computational Foundations of Conceptual Graphs
Graph-based Knowledge Representation: Computational Foundations of Conceptual Graphs
A general datalog-based framework for tractable query answering over ontologies
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
IJCAI'05 Proceedings of the 19th international joint conference on Artificial intelligence
Extending decidable cases for rules with existential variables
IJCAI'09 Proceedings of the 21st international jont conference on Artifical intelligence
Query answering under non-guarded rules in datalog+/-
RR'10 Proceedings of the Fourth international conference on Web reasoning and rule systems
Advanced processing for ontological queries
Proceedings of the VLDB Endowment
On rules with existential variables: Walking the decidability line
Artificial Intelligence
Walking the complexity lines for generalized guarded existential rules
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Two
Extending decidable existential rules by joining acyclicity and guardedness
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Two
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We consider rules that allow to assert the existence of new individuals, an ability called value invention in databases [AHV95]. These rules are of the form body → head, where the body and the head are function-free conjunctions of atoms, and variables that occur only in the head are existentially quantified, hence their name ∀∃-rules in [BLMS09, BLM10] or existential rules in [BMRT11, KR11]. Existential rules have long been studied in databases as high-level constraints called tuple generating dependencies (TGDs) [BV84]. Recently, there has been renewed interest for these rules in the context of ontology-based data access (OBDA), a new paradigm that seeks to exploit the semantics encoded in ontologies while querying data. The deductive database language Datalog could be seen as a natural candidate for expressing ontological knowledge in this context, however its limitation is that it does not allow for value invention, since all variables in a rule head necessarily occur in the rule body. Value invention has been recognized as a necessary prerequisite in an open-world perspective, where all individuals are not known a priori. It is in particular a feature of description logics (DLs), well-known languages dedicated to ontological representation and reasoning. This prerequisite motivated the recent extension of Datalog to existential rules, which gave rise to the Datalog +/- formalism [CGK08, CGL09].