- From: Brian McBride <bwm@hplb.hpl.hp.com>
- Date: Mon, 01 Jul 2002 08:06:49 +0100
- To: Piotr Kaminski <piotr@ideanest.com>, www-rdf-comments@w3.org
At 20:11 30/06/2002 -0700, Piotr Kaminski wrote: >Hi, > >In short: > >Do the subject and object of an rdfs:subClassOf statement have to both be >instances of the same (meta)class? They must both be instances of rdfs:Class, though this can be inferred rather than specified. There is no other constraint. I don't think this answers your question though. >In long: > >Are the following RDF triples valid (modulo syntax errors): > >MA rdf:type rdfs:Class >MA rdfs:subClassOf rdfs:Class >MB rdf:type rdfs:Class >MB rdfs:subClassOf rdfs:Class >A rdf:type MA >B rdf:type MB >A rdfs:subClassOf B There is nothing wrong with this set of triples, though they do look a little strange. It might best to explore what you think you are trying to say. What do you think the subClassOf triples are for? The following is also correct RDF: A rdfs:subClassOf B A schema aware RDF processor may conclude from this: A rdf:type rdfs:Class B rdf:type rdfs:Class >The only thing I can find is in the RDFS spec is section 2.3.2, which says >that "Only instances of rdfs:Class can have the rdfs:subClassOf property and >the property value is always of rdf:type rdfs:Class". The statements above >seem to satisfy this constraint. Yes they do, but the say more than is necessary to specify a simple subClassOf relationship. The minimum that is needed is a single triple: Human rdfs:subClassOf Animal . >The only related RDFCore WG issue I can find is rdfs-clarify-subClass-and >instance. > >Incidentally, does anyone know how UML deals with this? This is not the right place to ask UML questions. Brian
Received on Monday, 1 July 2002 03:07:42 UTC