- From: Hausenblas, Michael <michael.hausenblas@deri.org>
- Date: Fri, 11 Sep 2009 08:54:22 +0100
- To: "Ivan Herman" <ivan@w3.org>, "Tore Eriksson" <tore.eriksson@po.rd.taisho.co.jp>
- Cc: "Mark Birbeck" <mark.birbeck@webbackplane.com>, "RDFa TF list" <public-rdf-in-xhtml-tf@w3.org>, "Shane McCarron" <shane@aptest.com>
- Message-ID: <C6CFC0BE.83FA%michael.hausenblas@deri.org>
> Unfortunately, at least at the moment, there is no formal specification > for named graphs. Agree. And almost everyone I know agrees as well that this should be fixed in an updated RDF core (that is, model) in the very near future. Any plans? Cheers, Michael -- Dr. Michael Hausenblas LiDRC - Linked Data Research Centre DERI - Digital Enterprise Research Institute NUIG - National University of Ireland, Galway Ireland, Europe Tel. +353 91 495730 http://linkeddata.deri.ie/ http://sw-app.org/about.html > From: Ivan Herman <ivan@w3.org> > Organization: World Wide Web Consortium > Date: Fri, 11 Sep 2009 09:49:52 +0200 > To: Tore Eriksson <tore.eriksson@po.rd.taisho.co.jp> > Cc: Mark Birbeck <mark.birbeck@webbackplane.com>, RDFa TF list > <public-rdf-in-xhtml-tf@w3.org>, Shane McCarron <shane@aptest.com> > Subject: Re: Agenda Topic / Issue: Clarify the meaning of "ignore" with > respect to attributes that have no legal value > Resent-From: RDFa TF list <public-rdf-in-xhtml-tf@w3.org> > Resent-Date: Fri, 11 Sep 2009 07:50:31 +0000 > > > > Tore Eriksson wrote: >> Mark Birbeck <mark.birbeck@webbackplane.com> wrote: >>> The final piece of the jigsaw is to bring back in the earlier point, >>> i.e., that the spec allows us to create a triple from 'foobar' >>> provided that we don't put it into the default graph. In this case my >>> parser might place the 'unknown' triple into a separate graph: >>> >>> Default graph: >>> _:a foaf:name "Mark" . >>> >>> Graph A: >>> <#shane> ex:blah _:a . >>> >>> Now, as you can see, even though it's in a separate graph, I could >>> still run a SPARQL query over *both* graphs to yield the following >>> triples: >>> >>> <#shane> ex:blah _:a . >>> _:a foaf:name "Mark" . >>> >>> And since the parsing algorithm caused us to generate a bnode despite >>> not understanding 'ex:blah', then the triples in the two separate >>> graphs are 'aligned'. >> >> My understanding from reading "Named Graphs, Provenance and Trust" [1], >> is that blank nodes can't be shared between graphs, making this type of >> query impossible. Graph A has to be a superset of the default graph for >> this to work. >> > > Unfortunately, at least at the moment, there is no formal specification > for named graphs. Alas!, [1] does not constitute an authoritative > reference for a standard (although it may very well be the way to do it > technically!). Note that the SPARQL document does not make such strong > statements, so strictly referring to SPARQL Mark is probably right. But, > at the moment, this is a grey area:-( > > Ivan > > >> [1] http://www2005.org/cdrom/docs/p613.pdf >> >> Regards, >> >> Tore Eriksson >> >> _______________________________________________________________ >> <> dc:creator [ >> foaf:name "Tore Eriksson", >> "トーレ エリクソン"@jp; >> foaf:mbox_sha1sum "2bd9291b301f112775e118f96eb63314594b1a86"; >> foaf:workplaceHomepage <http://www.taisho.co.jp/> ]. >> >> >> > > -- > > Ivan Herman, W3C Semantic Web Activity Lead > Home: http://www.w3.org/People/Ivan/ > mobile: +31-641044153 > PGP Key: http://www.ivan-herman.net/pgpkey.html > FOAF: http://www.ivan-herman.net/foaf.rdf >
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Received on Friday, 11 September 2009 07:55:05 UTC