We extend RDF with the ability to represent property values that exist, but are unknown or partially known, using constraints. Following ideas from the incomplete information literature, we develop a semantics for this extension of RDF, called RDFi, and study SPARQL query evaluation in this framework.
Cite
@article{arxiv.1209.3756,
title = {Incomplete Information in RDF},
author = {Charalampos Nikolaou and Manolis Koubarakis},
journal= {arXiv preprint arXiv:1209.3756},
year = {2012}
}