Enhancements of linked data expressiveness for ontologies

The semantic web has received many contributions of researchers as ontologies which, in this context, i.e. within RDF linked data, are formalized conceptualizations that might use different protocols, such as RDFS, OWL DL and OWL FULL. In this article, we describe new expressive techniques which were found necessary after elaborating dozens of OWL ontologies for the scientific academy, the State and the civil society. They consist in: 1) stating possible uses a property might have without incurring into axioms or restrictions; 2) assigning a level of priority for an element (class, property, triple); 3) correct depiction in diagrams of relations between classes, between individuals which are imperative, and between individuals which are optional; 4) a convenient association between OWL classes and SKOS concepts. We propose specific rules to accomplish these enhancements and exemplify both its use and the difficulties that arise because these techniques are currently not established as standards to the ontology designer.