OWLlink: DIG for OWL 2

The OWLlink interface provides an implementation-neutral mechanism for accessing OWL reasoner functionality. In contrast to its DL-oriented predecessor DIG, OWLlink relies on OWL 2 for the primitives of the modelling language, and is thus fully compatible with the forthcoming incarnation of OWL. The OWLlink core introduced in this document covers (i) basic reasoner management, (ii) assertion of axioms and (iii) elementary ask functionality. The OWLlink extension mechanism allows to easily add any required functionality in a controlled way to the core language. We introduce OWLlink by providing a structural specification and a concrete binding of the interface that defines how OWLlink messages can be encoded in XML and sent over HTTP.