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S. Bischof, M. Krötzsch, A. Polleres, S. Rudolph:
"Schema-Agnostic Query Rewriting in SPARQL 1.1";
Talk: 13th International Semantic Web Conference, Riva del Garda; 10-19-2014 - 10-23-2014; in: "The Semantic Web - ISWC 2014", P. Mika et al. (ed.); LNCS/Springer, 8796 (2014), ISBN: 978-3-319-11963-2; 17 pages.

SPARQL 1.1 supports the use of ontologies to enrich query results
with logical entailments, and OWL 2 provides a dedicated fragment OWL QL
for this purpose. Typical implementations use the OWL QL schema to rewrite a
conjunctive query into an equivalent set of queries, to be answered against the
non-schema part of the data. With the adoption of the recent SPARQL 1.1 stan-
dard, however, RDF databases are capable of answering much more expressive
queries directly, and we ask how this can be exploited in query rewriting. We find
that SPARQL 1.1 is powerful enough to "implement" a full-fledged OWL QL rea-
soner in a single query. Using additional SPARQL 1.1 features, we develop a new
method of schema-agnostic query rewriti
ng, where arbitrary conjunctive queries
over OWL QL are rewritten into equivalent SPARQL 1.1 queries in a way that is
fully independent of the actual schema. This allows us to query RDF data under
OWL QL entailment without extracting or preprocessing OWL axioms.

Project Head Reinhard Pichler:
SEE: SPARQL Evaluation and Extensions