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Re: Common RDF parser bug?

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Tue, 22 Jan 2002 09:09:09 +0000
Message-Id: <5.1.0.14.0.20020122085109.00a790e8@0-mail-1.hpl.hp.com>
To: "Arthur Barstow" <barstow@mediaone.net>, <www-rdf-interest@w3.org>
At 13:43 19/01/2002 -0500, Arthur Barstow wrote:
>The following defect report against the W3C's ARP-based RDF Validator:
>
>  [1] http://lists.w3.org/Archives/Public/www-rdf-validator/2002Jan/0304.html
>
>suggests a violation of the following part of M&S:
>
>[[
>When a resource represents a reified statement; that is, it has an
>RDF:type property with a value of RDF:Statement, then that resource
>must have exactly one RDF:subject property, one RDF:object property,
>and one RDF:predicate property.
>]]

The RDFCore WG has discussed this issue and this is a bit embarrassing 
because I can't find the reference quickly, therefore I will couch this 
response in personal terms, rather than a WG statement.

I suggest we distinguish between the resource that is the reified statement 
and a description of that resource e.g. in an RDF graph.  The resource 
does, in a sense, have all three natural properties of subject, predicate 
and object.  However, that does not mean that an RDF graph has to represent 
all three properties.  I have recently found it useful to have a partial 
description of a statement.  The particular example I have in mind comes 
from an rdf schema for p3p I have been working on where I have statements 
of the form:

   <site> <collects> _:1 .
   _:1    <rdf:type> <rdf:Statement> .
   _:1     <rdf:predicate> <p3p:birthdate> .

which is a way of saying this site collects information about peoples 
birthdays.

It is my recollection that the RDFCore WG did decide to allow partial 
description of statements, and I'll try to find the reference.

Brian
Received on Tuesday, 22 January 2002 04:10:05 GMT

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