On Blank Nodes

  • Alejandro Mallea
  • Marcelo Arenas
  • Aidan Hogan
  • Axel Polleres
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7031)


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 across the W3C stack of RDF-related standards, to empirical analysis of RDF data publicly available on the Web. We then summarize alternative approaches to the problem, weighing up advantages and disadvantages, also discussing proposals for Skolemization.


Resource Description Framework Link Open Data Resource Description Framework Data Resource Description Framework Graph Existential Variable 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Alejandro Mallea
    • 1
  • Marcelo Arenas
    • 1
  • Aidan Hogan
    • 2
  • Axel Polleres
    • 2
    • 3
  1. 1.Department of Computer SciencePontificia Universidad Católica de ChileChile
  2. 2.Digital Enterprise Research InstituteNational University of Ireland GalwayIreland
  3. 3.Siemens AG ÖsterreichViennaAustria

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