This deliverable presents restricted variants of the OWL Lite, DL and Full species of the OWL ontology language, called OWL Lite−, OWL DL− and OWL Full−, respectively. OWL Lite− and OWL DL− are strict subsets of OWL Lite and OWL DL. They are limited in such a way that there exists a translation from both languages directly into the deductive database language Datalog. Thus, any OWL Lite− or OWL...

There are many query languages (QLs) that can be used to query RDF and OWL ontologies but neither type is satisfactory for querying OWL-DL ontologies. RDF-based QLs (RDQL, SeRQL, SPARQL) are harder to give a semantics w.r.t. OWL-DL and are more powerful than what OWL-DL reasoners can provide. DL-based QLs (DIG ask queries, nRQL) have clear semantics but are not powerful enough in the general ca...

Efficient query answering over ontologies is one of the most useful and important services to support Semantic Web applications. Approximation has been identified as a potential way to reduce the complexity of query answering over OWL DL ontologies. Existing approaches are mainly based on syntactic approximation of ontological axioms and queries. In this paper, we propose to recast the idea of ...

This deliverable presents restricted variants of the OWL Lite, DL and Full species of the OWL ontology language, called OWL Lite−, OWL DL− and OWL Full−, respectively. OWL Lite− and OWL DL− are strict subsets of OWL Lite and OWL DL. They are limited in such a way that there exists a translation from both languages directly into dunction-free logic programs, i.e., Datalog. Thus, any OWL Lite− or...

OWL 1.1 is a simple extension of the OWL DL species of the W3C OWLWeb Ontology Language. OWL 1.1 has been designed to provide some interesting and useful expressive additions to OWL DL while retaining the desirable characteristics of OWL DL, including decidability and implementability.

OWL DL corresponds to a Description Logic (DL) that is a fragment of classical first-order predicate logic (FOL). Therefore, the standard methods of automated reasoning for full FOL can potentially be used instead of dedicated DL reasoners to solve OWL DL reasoning tasks. In this paper we report on some experiments designed to explore the feasibility of using existing general-purpose FOL prover...

The Web Ontology Language (OWL) defines three classes of documents: Lite, DL and Full. All RDF/XML documents are OWL Full documents, some OWL Full documents are also OWL DL documents, and some OWL DL documents are also OWL Lite documents. This paper discusses parsing and species recognition – that is the process of determining whether a given document falls into the OWL Lite, DL or Full class. ...

Although OWL is rather expressive, it has a very serious limitation on datatypes; i.e., it does not support customised datatypes. It has been pointed out that many potential users will not adopt OWL unless this limitation is overcome, and the W3C Semantic Web Best Practices and Deployment Working Group has set up a task force to address this issue. This paper provides a solution for this issue ...