The Corese ontology representation language enables us to represent domain axioms which are taken into account when matching a query with an annotation [9]. We have proposed an RDF Rule extension to RDF and Corese integrates an inference engine based on forward chaining production rules. The rules are applied once the annotations are loaded in the system and before the query processing occurs. Hence, the annotation graphs are augmented by rule conclusions before the query graph is projected on them.
The inference rule language available is based on if then conceptual graph rules :
IF graph pattern THEN graph pattern
It is exploited in forward chaining at saturation, i.e. all rules are applied until no new statement is created. The inference engine uses graph projection to test the condition and graph join to process the conclusion.