Ensuring Soundness for SPARQL with Negation Using Completeness Statements

Talk by Fariz Darari

Location: APB 3027
Start: 27. April 2016 at 2:50 pm
End: 27. April 2016 at 3:50 pm
Research group: Computational Logic
Research group: Knowledge-Based Systems
Event series: KBS Seminar
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As RDF generally follows the Open-World Assumption, the use of negation in SPARQL queries might lead to unsound answers. Completeness statements have been proposed as metadata specifying that certain kinds of information are entirely recorded in an RDF data set. In this work, we leverage completeness statements to check whether we can guarantee soundness of query answering even when negation is used in SPARQL. We distinguish between the soundness of a specific answer of a graph pattern and the soundness of a graph pattern as a whole. We provide a formalization and characterize the problem of soundness checking via reduction to completeness checking. We also conduct an experimental evaluation to demonstrate the feasibility of our framework.