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Hi Tom Get lost in rdfs recursivity? not the first one :) > What is not clear to me, with a brief look at RDF Semantics, > is whether we are actually losing information by not saying > in 2010 what the term declaration said in 2008, i.e.: > > dct:AgentClass rdf:type rdfs:Class > dct:AgentClass rdfs:subClassOf rdfs:Class > > All classes are subclasses of rdfs:Resource, but are they > also all subclasses of rdfs:Class (i.e., can this second > triple simply be inferred)? > Actually not, but the other way round, yes. The first triple can be inferred from the second, since according to http://www.w3.org/TR/rdf-schema/#ch_subclassof "The rdfs:domain of rdfs:subClassOf is rdfs:Class." IOW ForAll (x,y) (x rdfs:subClassOf y) => (x rdf:type rdfs:Class) And BTW since we are in the logic land, seems to me no formal relation is declared between dct:Agent and dct:AgentClass Does the following hold ForAll x (x rdf:type dct:AgentClass) => ( x rdfs:subClassOf dct:Agent) (and the other way round). Or in less formal terms : An instance of dct:AgentClass is a subClass of dct:Agent? Yes? No? Bernard -- Bernard Vatant Senior Consultant Vocabulary & Data Engineering Tel: +33 (0) 971 488 459 Mail: [log in to unmask] ---------------------------------------------------- Mondeca 3, cité Nollez 75018 Paris France Web: http://www.mondeca.com Blog: http://mondeca.wordpress.com ----------------------------------------------------