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Re: [Q] how to reference a rdf schema in an rdf instance file ?

From: Sean B. Palmer <sean@mysterylights.com>
Date: Tue, 3 Jun 2003 13:12:32 +0100
Message-ID: <009201c329c9$6bb20520$09540150@localhost>
To: <danny666@virgilio.it>, <hgadm@cswebmail.com>
Cc: <www-rdf-interest@w3.org>

> > Do I use something like:
> > <rdf:Description
> > rdf:about=http://expm.rd.ambl.net/kno/transporters01.rdf>;
> > <rdfs:isDefinedBy
> > rdf:resource=http://expm.rd.ambl.net/kno.rdfs>;
>
> [...] if you want to do anything with the schema, you'll have to
> do this at the application level.

Well, note that the meaning of any RDF triple is defined by its
predicate, or, in the case of an rdf:type predicated triple, the
rdf:Class used as the object (cf. [1]). So linking an RDF instance to
its schema really means linking to the schemata for all of the
properties and classes used as I just described in the document. This,
clearly, is where rdf:aboutEachPrefix would've come in quite handy :-)

In lieu of that, though, people employ all sorts of tricks. CWM uses
the log:racine (the bit of the URI before the "#" if there is one) as
being the definition of a property/class. It's not a good situation,
though you don't really want to have to add "isDefinedBy" arcs for
each of the props/classes used. In fact, as you've stated Danny, it
wouldn't help anyway since the range of rdf:isDefinedBy is rather
loose.

So it might be a good idea, for a start, to have a subProperty of
isDefinedBy, as Aaron mentioned last year in an RDF Core meeting:-

"14:33:47 <danb_scri> aaron: creat a subproperty of isDefinedBy, whose
Range is Schema, and that is unambiguous per webont/owl." - RDF Core
notes, 2002-06-14 [2]

Or perhaps a link pointing to an intermediary where all of the [
rdfs:subPropertyOf rdfs:isDefinedBy ] links are housed. Lots of
choices; very little chance that anybody will implement them.

[1]
http://lists.w3.org/Archives/Public/www-rdf-comments/2001OctDec/0324
[2] http://ilrt.org/discovery/chatlogs/rdfcore/2002-06-14.txt

--
Sean B. Palmer, <http://purl.org/net/sbp/>
"phenomicity by the bucketful" - http://miscoranda.com/
Received on Tuesday, 3 June 2003 08:12:38 GMT

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