Reasoning with existential rules typically consists of checking whether a Boolean conjunctive query is satisfied by all models of a first-order sentence having the form of a conjunction of Datalog rules extended with existential quantifiers in rule-heads. To guarantee decidability, five basic decidable classes – linear, weakly-acyclic, guarded, sticky, and shy – have been singled out, together with several generalizations and combinations. For all basic classes, except shy, the important property of finite controllability has been proved, ensuring that a query is satisfied by all models of the sentence if, and only if, it is satisfied by all of its finite models. This paper takes two steps forward: (i) devise a general technique to facilitate the process of (dis)proving finite controllability of an arbitrary class of existential rules; and (ii) specialize the technique to complete the picture for the five mentioned classes, by showing that also shy is finitely controllable.

Finite Controllability of Conjunctive Query Answering with Existential Rules: Two Steps Forward

Giovanni Amendola;Nicola Leone;Marco Manna
2018-01-01

Abstract

Reasoning with existential rules typically consists of checking whether a Boolean conjunctive query is satisfied by all models of a first-order sentence having the form of a conjunction of Datalog rules extended with existential quantifiers in rule-heads. To guarantee decidability, five basic decidable classes – linear, weakly-acyclic, guarded, sticky, and shy – have been singled out, together with several generalizations and combinations. For all basic classes, except shy, the important property of finite controllability has been proved, ensuring that a query is satisfied by all models of the sentence if, and only if, it is satisfied by all of its finite models. This paper takes two steps forward: (i) devise a general technique to facilitate the process of (dis)proving finite controllability of an arbitrary class of existential rules; and (ii) specialize the technique to complete the picture for the five mentioned classes, by showing that also shy is finitely controllable.
2018
978-0-9992411-2-7
finite model reasoning, ontology-based query answering
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/278366
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