odrl:Duty leaf node

@prefix odrl: <http://www.w3.org/ns/odrl/2/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .

odrl:Duty a rdfs:Class,
        owl:Class,
        skos:Concept ;
    rdfs:label "Duty"@en ;
    rdfs:isDefinedBy odrl: ;
    rdfs:subClassOf odrl:Rule ;
    owl:disjointWith odrl:Permission,
        odrl:Prohibition ;
    skos:definition "The obligation to perform an Action"@en .