W3C home > Mailing lists > Public > www-rdf-interest@w3.org > August 2000


From: Francois-Paul Servant <hypersol@micronet.fr>
Date: Thu, 24 Aug 2000 00:44:23 +0200
Message-Id: <v04210103b5c9ef4bfac8@[]>
To: www-rdf-interest@w3.org

I imagine that it is possible to declare that dc:Subject  (for 
instance) is a subProperty of a property myProp that I define in a 
schema of my own. ("it is easy for anyone to say anything they want 
about any existing resource" ...). Is the following a correct syntax 
for that purpose:

<rdf:Description about="http://...dublincore#Subject">
      <rdfs:subPropertyOf rdf:resource="#myProp"/>

Assuming that this kind of declaration is actually allowed and makes 
sense, I come to another question, regarding cycles in subPropertyOf 
hierarchies, cycles that are forbidden by RDFS : "A property can 
never be declared to be a subproperty of itself, nor of any of its 
own subproperties." (RDFS 2.3.3)

This puzzles me a little bit, but I am confused about schemas, and I 
therefore could be missing something. My question is in fact about 
the link between schemas and applications dealing with them : I have 
the feeling that one application could be able to make something 
useful using a property p1 defined as a subproperty of a property p2, 
while another application would use p2 as a subproperty of p1.

Imagine for instance that you want to develop an application that 
produces and uses RDF files containing statements using a "keyword" 
property. You may want to define this property as a subproperty of 
dc:subject. This way, any application able to deal with dc:subject 
will be able to make something with your files.

But you also think that your application could make good use of any 
statement in any RDF file that uses dc:subject, as if it was a 
statement involving your own "keyword" property. In other words, you 
want your application to consider dc:Subject as a subProperty of 
"keyword", and you want therefore to declare that in a schema.

Does this makes sense?

Best Regards
Francois-Paul Servant
33 1 45 54 46 72 ; 170 rue de Lourmel 75015 PARIS
Received on Wednesday, 23 August 2000 18:44:45 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:44:24 UTC