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Existential rules have been proposed for representing ontological knowledge, specifically in the context of Ontology-Based Data Access. Entailment with existential rules is un-decidable. We focus in this paper on conditions that ensure the termination of a breadth-first forward chaining algorithm known as the chase. Several variants of the chase have been(More)
We propose a general framework for inconsistency-tolerant query answering within existential rule setting. This framework unifies the main semantics proposed by the state of art and introduces new ones based on cardinality and majority principles. It relies on two key notions: modifiers and inference strategies. An inconsistency-tolerant semantics is seen(More)
We consider existential rules (aka Datalog±) as a formalism for specifying ontologies. In recent years, many classes of existential rules have been exhibited for which conjunctive query (CQ) entail-ment is decidable. However, most of these classes cannot express transitivity of binary relations, a frequently used modelling construct. In this paper, we(More)