Thu, 21 Aug 2008 06:49:33 BST CiteULike: pablomendes's library [59 articles] http://www.citeulike.org/user/pablomendes/article/1380709 CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/pablomendes/article/1380709 <i>The Semantic Web - ISWC 2006 (2006), pp. 30-43.</i><br /><br />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. Semantics and Complexity of SPARQL Jorge Pérez Marcelo Arenas Claudio Gutierrez doi:10.1007/11926078_3 The Semantic Web - ISWC 2006 (2006), pp. 30-43. 2007-06-12T07:38:05-00:00 2006 The Semantic Web - ISWC 2006 30 43 query semantics sparql