- From: Eric Prud'hommeaux <eric@w3.org>
- Date: Wed, 26 Sep 2012 09:35:59 -0400
- To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
- Cc: Pat Hayes <phayes@ihmc.us>, Sandro Hawke <sandro@w3.org>, W3C RDF WG <public-rdf-wg@w3.org>
* Antoine Zimmermann <antoine.zimmermann@emse.fr> [2012-09-26 09:23+0200] > Le 26/09/2012 07:21, Pat Hayes a écrit : > > > >On Sep 25, 2012, at 9:28 PM, Sandro Hawke wrote: > > <skip/> > > >>> > >>>>PROPOSED: Our dataset syntax will have some standard mechanism > >>>>(to be determined within the next few weeks) through which a > >>>>Dataset serialization can include some RDF data about the > >>>>Dataset (that is, some metadata in the form of an RDF graph). > >>>+1, but note that AFAIKS this requires semantics which will be > >>>incompatible with some current use cases. > >> > >>Explain? > > > >OK, I will try again. > > > >People want to "label" a graph with a URI they are using to denote > >something else, eg a person. The same URI cannot denote two things at > >once. So the current proposal for a minimal semantics distinguishes > >the thing denoted from the graph "named", by having a GR-EXT function > >from things to graphs. But this means that when the URI is used in > >RDF, it denotes the something else, not the graph. So you don't get > >to use it in RDF metadata to refer to the graph. We could throw this > >semantics away, and say that the name really does denote the graph it > >"names", which has always made sense to me (and, apparently, to > >Peter, who is arguing the case right now), but then it can't also > >denote this other thing that people want it to denote, or perhaps > >better, want to have the freedom to make it denote. > > > >I can't help observing that this very basic point about URIs and > >naming has been bloody obvious since day one, and yet apparently this > >WG is STILL, after over a year, unable to gets its collective head > >around it. ... > The current proposal is not inconsistent with what Sandro wants. You > can say: > > { <n> a sd:Graph; > eg:hasSomeMetadataProp <x> . } > <n> { > #some triples > } > > Also, make it clear in the graph-metadata vocabulary that a sd:Graph > is, say, a graph description. Oh, BTW, it already exists and it is > on the verge of getting standardised. It's called SPARQL 1.1 Service > description. > > A quick look at the proposed semantics clearly shows that the > example is consistent. expanding the example to illustrate the dual use of the graph "identifier": { <Bob> a sd:Graph; eg:cached "2012009-26T11:25Z" . } <Bob> { <Bob> a foaf:Person . } so <Bob> denotes the union of a person and a graph. Jeni Tennison talks about this in terms of a pun http://www.jenitennison.com/blog/node/170 but the root of the issue is good old http-range 14. Two other range 14 resolutions are: hash: { <Bob> a sd:Graph; eg:cached "2012009-26T11:25Z" . } <Bob> { <Bob#me> a foaf:Person . } vs. slash: { <Bob> http:seeAlso <BobzPage> . <BobzPage> a sd:Graph; eg:cached "2012009-26T11:25Z" . } <BobPage> { <Bob> a foaf:Person . } Both of these impose restrictions which a lot of existing data do not follow. > <skip/> > -- > Antoine Zimmermann > ISCOD / LSTI - Institut Henri Fayol > École Nationale Supérieure des Mines de Saint-Étienne > 158 cours Fauriel > 42023 Saint-Étienne Cedex 2 > France > Tél:+33(0)4 77 42 83 36 > Fax:+33(0)4 77 42 66 66 > http://zimmer.aprilfoolsreview.com/ > -- -ericP
Received on Wednesday, 26 September 2012 13:36:36 UTC