Alejandro Mallea

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Blank nodes are defined in RDF as 'existential variables' in the same way that has been used before in mathematical logic. However, evidence suggests that actual usage of RDF does not follow this definition. In this paper we thoroughly cover the issue of blank nodes, from incomplete information in database theory, over different treatments of blank nodes(More)
In this paper we thoroughly cover the issue of blank nodes, which have been defined in RDF as 'existential variables'. We first introduce the theoretical precedent for existential blank nodes from first order logic and incomplete information in database theory. We then cover the different (and sometimes incompatible) treatment of blank nodes across the W3C(More)
1 Motivation Jointly with the release of RDF in 1999 as recommendation of the W3C, the natural problem of querying RDF data was raised. Since then, several designs and implementations of RDF query languages have been proposed (see [9] and [7] for detailed comparisons of RDF query languages). In 2004, the RDF Data Access Working Group released a first public(More)
of Toronto in 2005. My research interests are in different aspects of databases, such as expressive power of query languages, database semantics, inconsistency handling, database design, XML databases, data exchange, metadata management and database aspects of the Semantic Web. I have received an IBM Ph. for my Ph.D. dissertation " Design Principles for XML(More)
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