W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > May 2002

Re: RDF Graph questions

From: patrick hayes <phayes@ai.uwf.edu>
Date: Tue, 28 May 2002 18:04:09 -0500
Message-Id: <p05111715b919bcc5f428@[]>
To: Dan Brickley <danbri@w3.org>
Cc: w3c-rdfcore-wg@w3.org
>On Fri, 24 May 2002, Dave Beckett wrote:
>>  >>>Jeremy Carroll said:
>>  > Second a few questions.
>>  >
>>  > 1. Are there unattached nodes in an RDF graph?
>>  No; since we base our describe the rdf graph as triples
>>  as node->arc->node rather than any other form.  If this is not the
>>  case then N-Triples in insufficient to connect the model theory and
>>  syntax.
>>  > 2. Can any URI ref be a property name or must there be some associated
>>  > namespace?
>>  Any URI ref.
>No, not _any_ URI ref.
>Some URI refs don't name properties.

Well, then any assertion made using them as property names will be 
false; but still, its not meaningless, so I think we should allow it. 
There might be some reason for someone to treat a phone number as a 
property; its not totally crazy. In general, I don't think we are in 
a position to say that something definitely does not name a property.


>Arguably, all the phone: ones, all the mailto: ones, and a huge % of all
>the http:// URIrefs too.
>But I think I agree with (what I take to be) your general point. There are
>many URIrefs that we can take as naming URIrefs which aren't (for various
>reasons) going to have an RDF/XML document derferencable.
>However, the fact that they name RDF properties means that they can be
>used in RDF/XML instance data using the XML namespace mechanism, so in
>that sense they are associated with a namespace. Or they are a namespace.
>Or they can be written about using XML namespaces.
>    This is pretty clear from M&S and we've mentioned this
>>  a few times in passing with respect to the issues related to
>>  writing them as qnames.
>>  (XML) Namespaces are artifacts of the RDF/XML serialization and are
>>  not in the current model.

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Received on Tuesday, 28 May 2002 19:03:28 UTC

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