- From: Graham Klyne <GK@NineByNine.org>
- Date: Wed, 10 Oct 2001 16:13:56 +0100
- 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 UTC