Chapter

The Semantic Web - ISWC 2006

Volume 4273 of the series Lecture Notes in Computer Science pp 30-43

Semantics and Complexity of SPARQL

  • Jorge PérezAffiliated withUniversidad de Talca
  • , Marcelo ArenasAffiliated withPontificia Universidad Católica de Chile
  • , Claudio GutierrezAffiliated withUniversidad de Chile

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Abstract

SPARQL is the W3C candidate recommendation query language for RDF. In this paper we address systematically the formal study of SPARQL, concentrating in its graph pattern facility. We consider for this study simple RDF graphs without special semantics for literals and a simplified version of filters which encompasses all the main issues. We provide a compositional semantics, prove there are normal forms, prove complexity bounds, among others that the evaluation of SPARQL patterns is PSPACE-complete, compare our semantics to an alternative operational semantics, give simple and natural conditions when both semantics coincide and discuss optimization procedures.