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

From: Art Barstow <barstow@w3.org>
Date: Wed, 10 Oct 2001 09:11:51 -0400
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: Graham Klyne <GK@NineByNine.org>, RDF core WG <w3c-rdfcore-wg@w3.org>
Message-ID: <20011010091151.A20833@w3.org>
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.  I probably remove the
NOTE part.

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/

Art
---

> 
> Brian
> 
> 
> 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)
> > 
Received on Wednesday, 10 October 2001 09:12:57 EDT

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