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Re: N3 and N-Triples (was: RDF in HTML: Approaches)

From: Simon Raboczi <raboczi@PIsoftware.com>
Date: Fri, 7 Jun 2002 11:43:44 +1000
To: www-rdf-interest@w3.org
Message-ID: <20020607114344.B1014@pisoftware.com>

On Thu, Jun 06, 2002 at 10:51:19AM +0100, Seaborne, Andy wrote:
> 
> If an RDF processor reads in the same file twice, are the bNodes the same or
> different?
> 
> For compatibility with current RDF syntax, implicit bNodes in the current
> syntax yield different bnodes in the graph created.  But there is a choice
> as to whether an explicit bNode (one labeled in the syntax) is scoped to the
> file read operation (and hence creates different bNodes) or whether they get
> unique labels in the disjoint space.
> 
> It means part of the system (an RDF application) on one machine can talk
> about the bNodes on another machine (the source of the graph).

I think this misses the point of having bNodes at all.  If the other machine
agreed that a node was stable enough for you to point at it, it would've
issued it as a named node with a URI.  By issuing it as a bNode, it's denying
you permission to refer to it: the resource is being passed to you by value
rather than by reference, and the originating system is free to delete the
original.

I believe the correct behavior in the case of loading the same file twice
is to obtain the duplicate bNodes.  The determination that bNodes are equal
(by property value) isn't really core RDF's concern; that'd seem to be in
OWL's territory.

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Received on Thursday, 6 June 2002 21:43:51 GMT

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