Combining decidability paradigms for existential rules

Gottlob, Georg; Manna, Marco; Pieris, Andréas

doi:10.1017/s1471068413000550

Cited by 12 publications

(6 citation statements)

References 26 publications

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“…A completely different proof of the above theorem follows directly from the results in [47] for the class of GTGDs, and from those in [48] for the class of WGTGDs.…”

Section: Tgds With Multiple-atom Headsmentioning

confidence: 99%

Taming the Infinite Chase: Query Answering under Expressive Relational Constraints

Calì¹,

Gottlob²,

Kifer³

2013

jair

215

485

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The chase algorithm is a fundamental tool for query evaluation and for testing query containment under tuple-generating dependencies (TGDs) and equality-generating dependencies (EGDs). So far, most of the research on this topic has focused on cases where the chase procedure terminates. This paper introduces expressive classes of TGDs defined via syntactic restrictions: guarded TGDs (GTGDs) and weakly guarded sets of TGDs (WGTGDs). For these classes, the chase procedure is not guaranteed to terminate and thus may have an infinite outcome. Nevertheless, we prove that the problems of conjunctive-query answering and query containment under such TGDs are decidable. We provide decision procedures and tight complexity bounds for these problems. Then we show how EGDs can be incorporated into our results by providing conditions under which EGDs do not harmfully interact with TGDs and do not affect the decidability and complexity of query answering. We show applications of the aforesaid classes of constraints to the problem of answering conjunctive queries in F-Logic Lite, an object-oriented ontology language, and in some tractable Description Logics.

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“…A completely different proof of the above theorem follows directly from the results in [47] for the class of GTGDs, and from those in [48] for the class of WGTGDs.…”

Section: Tgds With Multiple-atom Headsmentioning

confidence: 99%

Taming the Infinite Chase: Query Answering under Expressive Relational Constraints

Calì¹,

Gottlob²,

Kifer³

2013

jair

215

485

View full text Add to dashboard Cite

show abstract

“…The problem of allowing such additional symbols in these constructions is certainly interesting and worth investigating in the future. Third, it is interesting to study the problem of knowledge exchange for richer ontology formalisms, such as the DLs of the ALC-family, DLs with number restrictions or functionality, or existential rule languages/Datalog ± [66,67,68]. The aim would be to understand for which variants of such formalisms the existing techniques can be extended, and which variants instead would require a novel approach.…”

Section: Concluding Remarks and Future Workmentioning

confidence: 99%

Knowledge base exchange: The case of OWL 2 QL

Arenas

Botoeva

Calvanese

et al. 2016

Artificial Intelligence

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In this article, we define and study the problem of exchanging knowledge between a source and a target knowledge base (KB), connected through mappings. Differently from the traditional database exchange setting, which considers only the exchange of data, we are interested in exchanging implicit knowledge. As representation formalism we use Description Logics (DLs), thus assuming that the source and target KBs are given as a DL TBox+ABox, while the mappings have the form of DL TBox assertions. We define a general framework of KB exchange, and study the problem of translating the knowledge in the source KB according to the mappings expressed in OWL 2 QL, the profile of the standard Web Ontology Language OWL 2 based on the description logic DL-Lite R . We develop novel gameand automata-theoretic techniques, and we provide complexity results that range from NLogSpace to ExpTime.

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“…In the first case, the already seen graph of rule dependencies may be used to split the study of a rule set into the study of the sets that are formed by its strongly connected components. In the second category, weakly-sticky sets of rules [CGP10] and tameness [GMP13] have been proposed, allowing to combine (under some restrictions) sticky sets of rules with weakly-acyclic sets of rules for the former, and with guarded rules for the latter.…”

Section: Outside Of the Classification And Combinationsmentioning

confidence: 99%

An Introduction to Ontology-Based Query Answering with Existential Rules

Mugnier

Thomazo

2014

Lecture Notes in Computer Science

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International audienceThe need for an ontological layer on top of data, associated with advanced reasoning mechanisms able to exploit ontological knowl-edge, has been acknowledged in the database, knowledge representation and Semantic Web communities. We focus here on the ontology-based data querying problem, which consists in querying data while taking on-tological knowledge into account. To tackle this problem, we consider a logical framework based on existential rules, also called Datalog ± . In this course, we introduce fundamental notions on ontology-based query answering with existential rules. We present basic reasoning techniques, explain the relationships with other formalisms such as lightweight de-scription logics, and review decidability results as well as associated al-gorithms. We end with ongoing research and some challenging issues

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Combining decidability paradigms for existential rules

Cited by 12 publications

References 26 publications

Taming the Infinite Chase: Query Answering under Expressive Relational Constraints

Taming the Infinite Chase: Query Answering under Expressive Relational Constraints

Knowledge base exchange: The case of OWL 2 QL

An Introduction to Ontology-Based Query Answering with Existential Rules

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