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
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
Terminological cycles in a description logic with existential restrictions
IJCAI'03 Proceedings of the 18th 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
Efficient Query Answering for OWL 2
ISWC '09 Proceedings of the 8th International Semantic Web Conference
Query answering under non-guarded rules in datalog+/-
RR'10 Proceedings of the Fourth international conference on Web reasoning and rule systems
On rules with existential variables: Walking the decidability line
Artificial Intelligence
Ontological queries: Rewriting and optimization
ICDE '11 Proceedings of the 2011 IEEE 27th International Conference on Data Engineering
Optimized query rewriting for OWL 2 QL
CADE'11 Proceedings of the 23rd international conference on Automated deduction
Ontological query answering with existential rules
RR'11 Proceedings of the 5th international conference on Web reasoning and rule systems
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
A sound and complete backward chaining algorithm for existential rules
RR'12 Proceedings of the 6th international conference on Web Reasoning and Rule Systems
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We address the issue of Ontology-Based Data Access which consists of exploiting the semantics expressed in ontologies while querying data. Ontologies are represented in the framework of existential rules, also known as Datalog+/-. We focus on the backward chaining paradigm, which involves rewriting the query (assumed to be a conjunctive query, CQ) into a set of CQs (seen as a union of CQs). The proposed algorithm accepts any set of existential rules as input and stops for so-called finite unification sets of rules (fus). The rewriting step relies on a graph notion, called a piece, which allows to identify subsets of atoms from the query that must be processed together. We first show that our rewriting method computes a minimal set of CQs when this set is finite, i.e., the set of rules is a fus. We then focus on optimizing the rewriting step. First experiments are reported in the associated technical report.