Abstract. We present an extension of the ontology-based data access platform Ontop that supports answering SPARQL queries under the OWL 2 QL direct semantics entailment regime for data instances stored in relational databases. On the theoretical side, we show how any input SPARQL query, OWL 2 QL

Abstract. The SPARQL query language is currently being extended by W3C with so-called entailment regimes, which define how queries are evaluated under more expressive semantics than SPARQL’s standard simple entailment. We describe a sound and complete algorithm for the OWL Direct Semantics

The SPARQL query language is currently being extended by the World Wide Web Consortium (W3C) with so-called entailment regimes. An entailment regime defines how queries are evaluated under more expressive semantics than SPARQL’s standard simple entailment, which is based on subgraph matching

Abstract. The SPARQL query language is currently being extended by W3C with so-called entailment regimes, which define how queries are evaluated under more expressive semantics than SPARQL’s standard simple entailment. We describe a sound and complete algorithm for the OWL Direct Semantics

Abstract. This chapter accompanies the lecture on SPARQL with entailment

Abstract. The problem of SPARQL query containment is defined as determining if the result of one query is included in the result of another for any RDF graph. Query containment is important in many areas, including information integration, query optimization, and reasoning about Entity

The OWL Web Ontology Language is a new formal language for representing ontologies in the Semantic Web. OWL has features from several families of representation languages, including primarily Description Logics and frames. OWL also shares many characteristics with RDF, the W3C base of the Semantic

equally well to represent sets and tuples. Such structures allow great flexibility in data representation What query language is appropriate for such structures? Here we propose a simple language UnQL for querying data organized as a rooted, edge-labeled graph. In this model, relational data may

Abstract. We study the semantics of SPARQL queries with optional matching features under entailment regimes. We argue that the normative semantics may lead to answers that are in conflict with the intuitive mean-ing of optional matching, where unbound variables naturally represent unknown

Abstract. W3C currently extends the SPARQL query language with so-called entailment regimes, which define how queries are evaluated using logical entailment relations. We describe a sound and complete algorithm for the OWL Direct Semantics entailment regime. Since OWL’s Direct Semantics is based