Publication date
August 2009
DOI Publisher
Association for Computing Machinery (ACM)Abstract
Artículo de publicación ISISPARQL is the W3C candidate recommendation query lan- guage 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 se- mantics coincide and discuss optimization procedures.Fondecyt 1070732 1090565 1070348 C...