- 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>
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 UTC