- From: Antoine Zimmermann <antoine.zimmermann@insa-lyon.fr>
- Date: Fri, 08 Apr 2011 16:13:14 +0200
- To: Richard Cyganiak <richard@cyganiak.de>
- CC: public-rdf-wg@w3.org, Ian Davis <me@iandavis.com>
Le 08/04/2011 16:00, Richard Cyganiak a écrit : > On 8 Apr 2011, at 14:29, Antoine Zimmermann wrote: >> how one can say that the content of a g-box at a certain point in time is a certain g-snap? >> If named graphs are in fact named g-box, then how can one relate this name to the content at a certain point in time (for instance, to talk about a certain version of the g-box)? > > <my-gbox> dc:hasVersion<my-gbox/2011-04-08> . > <my-gbox/2011-04-08> dc:date "2011-04-08"^xsd:date This does not tell me what is in <my-gbox/2011-04-08>. > (Or use another vocabulary with stronger versioning semantics instead of DC) > >> Another question is, how can one specify the differences between two versions of a g-box? For instance, g-box@2011-04-01 extends g-box@2010-04-01 by adding the triples { :x :y :z . :a :b :c .}. >> How can I explicit refer to these specific 2 triples if I can only talk about g-boxes? > > Make a new g-box containing these two triples, and use some vocabulary to say that A=B+C How do you make a gbox containing those two triples? >> As other people suggested, I have the impression that there are use cases for identifying g-boxes and use cases for identifying g-snaps. > > I assert that all these use cases can be addressed by declaring some g-boxes immutable. One can have use case specific vocabularies that state which g-boxes are mutable and which not. Note that there is an isomorphism between g-snaps and immutable g-boxes. Perhaps but you don't say how I define the content of an immutable gbox. >> My opinion at the moment is that we use graph literals for g-snaps (so we don't have to give them names, they are fully defined by their lexical value) > > How do I say that a certain unnamed literal g-snap contains 123 triples? You don't. The idea is that we only refer to g-boxes. g-snaps are given by their triples explicitly. > >> and we name g-boxes. That is, in TriG: >> >> :G1 { :a :b :c . :x :y "{:u :v :w.}"^^rdf:gsnap } > > I don't understand what this is supposed to mean. This is just a TriG document. At the moment, there is no well defined semantics for it, so I'm just using it at a syntax to somehow connect the URI of the g-box (G1) to a certain g-snap (between the outermost curly brackets). The literal inside that g-snap is just a typed literal, perfectly valid in RDF. A system does not necessarily need to understand that specific datatype, but the idea is to interpret this as a g-snap. > > You cannot write down a g-box. You can only write down a g-snap. The best you can do is saying that a g-box of a certain name has a certain g-snap as its content right now. Having two different syntactic constructs for writing down g-boxes and g-snaps is a confusing mess that solves no problem. At some point either you should be able to talk about specific triples in g-boxes or in g-snaps. It is fine for me to have immutable g-boxes to be able to talk about fixed g-snaps, but I still need a way to make explicit the triples inside. > > Best, > Richard > > >> >> :G1 identifies a g-box which somehow is related^{1} to the g-snap: >> >> :a :b :c . >> :x :y "{:u :v :w.}"^^rdf:gsnap >> >> and "{:u :v :w.}"^^rdf:gsnap is identifying exactly the g-snap: >> >> :u :v :w. >> >> I can also say: >> >> :G1 :earlierVersion [ >> :content "{:a :b :c .}"^^rdf:gsnap . >> :atTime "2010-04-01"^^xsd:date . >> ] >> >> >> ----Footnote---- >> {1} I leave the relationship between :G1 and the content inside the curly brackets to a later email. >> >> >> AZ. -- Antoine Zimmermann Researcher at: Laboratoire d'InfoRmatique en Image et Systèmes d'information Database Group 7 Avenue Jean Capelle 69621 Villeurbanne Cedex France Tel: +33(0)4 72 43 61 74 - Fax: +33(0)4 72 43 87 13 Lecturer at: Institut National des Sciences Appliquées de Lyon 20 Avenue Albert Einstein 69621 Villeurbanne Cedex France antoine.zimmermann@insa-lyon.fr http://zimmer.aprilfoolsreview.com/
Received on Friday, 8 April 2011 14:13:47 UTC