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On the Semantics of SPARQL Queries with Optional Matching under Entailment Regimes
| Citations: | 4 - 2 self |
BibTeX
@MISC{Kostylev_onthe,
author = {Egor V. Kostylev and Bernardo Cuenca Grau},
title = {On the Semantics of SPARQL Queries with Optional Matching under Entailment Regimes},
year = {}
}
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Abstract
Abstract. We study the semantics of SPARQL queries with optional matching features under entailment regimes. We argue that the normative semantics may lead to answers that are in conflict with the intuitive mean-ing of optional matching, where unbound variables naturally represent unknown information. We propose an extension of the SPARQL algebra that addresses these issues and is compatible with any entailment regime satisfying the minimal requirements given in the normative specification. We then study the complexity of query evaluation and show that our extension comes at no cost for regimes with an entailment relation of reasonable complexity. Finally, we show that our semantics preserves the known properties of optional matching that are commonly exploited for static analysis and optimisation. 1
Keyphrases
optional matching entailment regime sparql query reasonable complexity query evaluation unknown information known property intuitive mean-ing unbound variable optional matching feature static analysis sparql algebra normative specification entailment relation minimal requirement normative semantics
