- From: Pat Hayes <phayes@ihmc.us>
- Date: Tue, 1 Mar 2011 16:59:06 -0600
- To: David Wood <david.wood@talis.com>
- Cc: RDF WG <public-rdf-wg@w3.org>
On Mar 1, 2011, at 12:52 PM, David Wood wrote: > > On Mar 1, 2011, at 05:32, Nathan wrote: > >> Hi David, >> >> Sorry, I've realised the below is wrong, so corrected: >> >> Nathan wrote: >>> David Wood wrote: >>>> On Feb 24, 2011, at 13:12, Pat Hayes wrote: >>>> >>>>> It is much simpler: it is just wanting the WG to acknowledge that "an RDF graph" can either be a mathematical set, or it can be some kind of document or data structure or file than can be transmitted over a computer network. But it can't be both. >>>> >>>> What is the difference between an "RDF graph" and a RESTful "resource"? What is the difference between an "RDF graph token" and a RESTful "representation"? >>> REST maps a resource to a set of values over time, each single value has a 1:N relationship with representations, "RDF Graph" (the mathematical set, platonic abstraction, g-snap) equates to a single value, and "RDF Graph Token" equates to a representation of that single value. >> >> REST maps a resource to a set of values over time, each single value is a representation, representation equates to "RDF Graph Token" (a chunk of rdf/xml or turtle, a g-text in Sandro's mail). >> >> The g-snap, or abstract graph, isn't a concept which relates to any REST concept, rather it is something specific to our RDF use-cases, in that we have a platonic abstraction, a mathematical set of triples, which we juggle different realizations of (from in memory structures through to serializations and so forth). >> >> So, to re-answer your question, "RDF Graph" is a term we've used to refer to both the abstract set of triples, and the realizations of. The only thing which equates anywhere near a "RESTful resource" in our communities are "Named Graphs" and of course linked data which uses RESTful resources, we GET <u> to retrieve a realization of an abstract set of triples, to get some RDF in some format. >> > > > Pardon me for saying so, but that doesn't make sense to me. > > A RESTful resource may be anything: "the intended *conceptual* target of a hypertext reference" was one way Roy Fielding put it (emphasis mine). There is no reason I can see that an abstract, mathematical concept cannot be a RESTful resource. I see the opposite. Roy did not always make sense. But he did say, quite clearly and repeatedly, that RESTful resources are functions from times to representations. A mathematical set is not a function from times to anything. So, a mathematical set cannot be a RESTful resource. > > Andy neatly ducked the question of mapping to a resource: > > On Mar 1, 2011, at 06:30, Andy Seaborne wrote: >> g-box - place holding a sequence-over-time of values >> g-snap - one such value >> g-text - the REST representation. > > > Instead, I suggest something like this: > > g-box - a REST resource, over time. > g-snap - a conception of the REST resource at the time it is addressed. > g-text - the REST representation. I'm cool with that, provisionally. I have no idea what "conception of" means here, however. In my vocabulary, a conception of anything is basically a psychological notion. I would vastly prefer to avoid going in that direction. The notion of a mathematical or abstract model is much better defined and less controversial. And we do have to relate whatever we say to the existing RDF specs, which define a graph to be a set (not a conception.) Pat > > That seems to address Pat's concern and stays very Webby. > > Regards, > Dave > > > >> Apologies, just had to correct myself there. >> >> Best, >> >> Nathan > > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Tuesday, 1 March 2011 22:59:45 UTC