The ontology representation language of Corese is built upon RDFS. Basically, the expressivity of RDFS enables the representation of ontologies and in particular their hierarchies of concept types and relation types. Corese thus takes into account subsumption links between concepts and between relations when matching a query with an annotation. The ontology representation language of Corese also enables us to represent domain axioms which are taken into account when matching a query with an annotation.
Annotations are represented in RDF and related to the RDF Schema representing the ontology they are built upon. The query language is also built upon RDF; for each query, an RDF graph is generated, related to the same RDF Schemas as the one of the annotations upon which it is to be matched.
The Corese engine internally works on conceptual graphs. When matching a query with an annotation, according to their common ontology, both RDF graphs and their schemas are translated in the conceptual graph model [15,11]. Through this translation, Corese takes advantage of the existing work of the knowledge representation community leading to reasoning capabilities of this language.