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Re: Resolution of: #rdfms-identity-anon-resources

From: Graham Klyne <GK@NineByNine.org>
Date: Wed, 10 Oct 2001 16:13:56 +0100
Message-Id: <5.1.0.14.2.20011010161304.038d4080@joy.songbird.com>
To: Art Barstow <barstow@w3.org>
Cc: RDF core WG <w3c-rdfcore-wg@w3.org>
Art,

OK, I'll re-post the with the addition of explicit answers to those points.

At 09:11 AM 10/10/01 -0400, you wrote:
>On Tue, Oct 09, 2001 at 11:34:42AM +0100, Brian McBride wrote:
> > There seem to be no responses to Graham's proposed resolution text, and 
> I assume
> > therefore no dissent.  This will be on Friday's telecon agenda.
>
>This issue:
>
>   http://www.w3.org/2000/03/rdf-tracking/#rdfms-identity-anon-resources
>
>contains the following questions:
>
>[[
>
>[1.] Should anonymous resources have URI's?
>
>[2.] If so, should the be clearly distinguishable as parser generated URI's?
>
>[3.] Should there be a standard algorithm for generating URI's which ensures
>  that different parsers generate the same URI's from the same source
>  input document?
>
>[4.] How might these automatically generated URI's be affected by changes
>  in the source document?
>]]
>
>It appears questions #3 and #4 above are not explicitly addressed in
>the proposed resolution.  I'd like to see the resolution address #3; I'm
>indifferent about whether #4 should be addressed in the resolution.
>
>If we're going down the wordsmithing path, I think I'd avoid
>talking about "normal" usage of bNodes; otherwise, it seems like
>ab-normal would also need to be defined.

OK, I've made that more explicit -- see separate message

>   I probably remove the
>NOTE part.

This isn't verbatim text for the new document, so I don't think it 
harms.  Meanwhile, I think it's worth having some record of our 
considerations in getting to this point.

>It also seems like some test cases that shows how an "un-named
>resource" in RDF/XML gets mapped into a bNode (and NOT a URI)
>in N-Triples would be useful.  I created some test cases and
>placed them in:
>
>  http://www.w3.org/2000/10/rdf-tests/rdfcore/rdfms-identity-anon-resources/

Yes, that's helpful, thanks -- I'm checking them:
   Test001 -- OK
   Test002 -- OK
   Test003 -- OK
   Test004 -- OK
   Test005 -- OK (but I don't see that it's materially different from 
Test003 for the purposes of this issue)

#g
--

> > Graham Klyne wrote:
> >
> > > With respect to the issue:
> > > [1] http://www.w3.org/2000/03/rdf-tracking/#rdfms-identity-anon-resources
> > >
> > > Being a revision of my previous message:
> > > [2] http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Aug/0030.html
> > >
> > > And citing the model theory document:
> > > [3] http://www.w3.org/TR/2001/WD-rdf-mt-20010925/
> > >
> > > I propose the following resolution text:
> > >
> > > [[[
> > > 1. Resources that are described but not named in an XML serialization
> > > (by rdf:ID or rdf:about) are represented in an RDF abstract graph by
> > > nodes that do not have any associated URI.  Such nodes, called bNodes
> > > (from blank nodes) are thereby distinguishable from other described
> > > resource nodes, which do have an associated URI-reference label.
> > >
> > > To directly address the question of the issue:  a so-called anonymous
> > > resource has no URI.
> > >
> > > 2. To reflect un-named descriptions in N-triples, local names must be
> > > introduced (i.e. of the form '_:name').  These names are not URIs, and
> > > their scope is the N-triples document in which they appear.
> > >
> > > 3. In normal use, the meaning of bNode is to assert the existence of at
> > > least one resource which is the subject and/or object of properties as
> > > indicated by the graph.  This is covered more formally by the Model
> > > Theory [3], section 2.  See also the anonymity lemmas in section 3.2.
> > >
> > > NOTE:  it has been proposed that the RDF graph syntax can be used for
> > > form a query, in which bNodes may be interpreted as query variables.
> > > This resolution confirms that bNodes can be distinguished from other
> > > labelled nodes within the graph syntax, but is silent about if and how
> > > the graph syntax might be used to represent a query.
> > > ]]]
> > >
> > > #g
> > >
> > >
> > > ------------
> > > Graham Klyne
> > > (GK@ACM.ORG)
> > >

------------
Graham Klyne
(GK@ACM.ORG)
Received on Wednesday, 10 October 2001 12:25:36 EDT

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