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linking reification to reified (was: Re: reification "subagenda")

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Thu, 14 Feb 2002 18:52:42 -0500
Message-Id: <p0510142cb891fabeec98@[192.168.0.6]>
To: Frank Manola <fmanola@mitre.org>
Cc: w3c-rdfcore-wg@w3.org

>4.  If decisions are made about #1-#3, one of the issues we then 
>need to decide is whether we need (or can) do anything else to 
>support provenance in RDF 1.0.  It seems to me that fully dealing 
>with provenance may require addressing the following:
>
>a. being able to actually identify the specific triple (the 
>"literal" triple;  what the guy actually said, including the literal 
>URIs), as opposed to a *description* of that triple.

It occurs to me that the obvious way to do that would be to have 
another special property <rdf:source> of a reification, so the 
'normal' case would be 5 triples (a quintriplet?) rather than 4, 
where the extra one links the subject to its source, using an 
appropriate URI, eg (check it out)

      _:r <rdf:type> <rdf:Statement> .
      _:r <rdf:subject> _:x .
      _:r <rdf:predicate> <http://example.org/dt#USdate> .
      _:r <rdf:object> "05-08-67" .
      _:r <rdf:source> <http://www.agfa.com/w3c/n3/p7.nt>

Then we really could say some MT stuff about what it has to mean, eg 
this is *false* if that graph doesn't contain the described triple.

Incidentally, this example makes me wonder: if one reifies a triple 
containing a blank node as subject, what exactly does one say is the 
object of <rdf:subject> in that case??? Seems we need a way to say

_:r <rdf:subject> _:x .
_:x <rdf:type> <rdfs:BlankNode> .

??

Pat

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Received on Thursday, 14 February 2002 18:52:42 EST

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