- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Tue, 30 Aug 2011 12:37:27 +0100
- To: Jesse Weaver <weavej3@rpi.edu>
- Cc: ivan@w3.org, public-rdf-wg@w3.org
Hi Jesse, On 29 Aug 2011, at 20:42, Jesse Weaver wrote: > It would be nice to be able to say in a single statement: > > <group> <contains> <thing> . > > You cannot do this with RDF collections. You can do it with RDF > containers using rdfs:member. Not really. What you certainly can do is this: <group> <contains> [ a rdfs:Bag; rdf:_1 <thing>.]. and this implicitly uses rdfs:member because rdf:_1 is a subproperty. The usage <group> rdfs:member <thing>. is not documented anywhere in the RDF specifications. I don't think it is the intended usage. The specifications are too fuzzy to allow a definitive statement on whether it's correct or not. They don't assign any meaning to the property at all, except that the property is implied by membership in a Seq, Bag or Alt. (Which is a failure of the spec, and one of the reasons why containers are best avoided.) So, the usage you propose assumes that rdfs:member has a meaning that is sort of implied by the property's name, but not given explicitly in the spec. As Dan said, dcterms:hasPart is more appropriate for your use case. Best, Richard > It seems that we should have some way of > doing this, regardless of whether RDF containers are deprecated. > > Jesse Weaver > Ph.D. Student, Patroon Fellow > Tetherless World Constellation > Rensselaer Polytechnic Institute > http://www.cs.rpi.edu/~weavej3/ > ==============Original message text=============== > On Mon, 29 Aug 2011 8:09:22 EDT Ivan Herman wrote: > > Jesse, > > - There is no formal resolution on containers yet. There has been some > discussions, and deprecating containers has indeed been raised as one of > the candidates. > > - However, your usage of rdfs:member v.a.v. lists (a.k.a. collections) is > a slightly different question. At them moment, there is no semantic > relationships in RDFS between the terms used for lists (rdf:first, > rdf:next, or rdf:List) and rdfs:member. Put it another way if I have > > <a> <b> (<c> <d> <e>) . > > I cannot infer something like > > <c> rdfs:member _:a . # _:a is the 'head' of the list above. > > I may have misunderstood what you said, though. > > Ivan > > > > > On Aug 26, 2011, at 20:59 , Jesse Weaver wrote: > >> Hello RDF working group. >> >> Has there been consensus concerning deprecation of RDF containers in 1.1? >> Specifically, I am curious about the rdfs:member property. It is very >> useful for stating membership of something in a uniform way (unlike using >> rdf:_1, rdf:_2, ...) and in a single triple (unlike using rdf:first and >> rdf:rest). I am well aware of the distinction between containers and >> collections, but it seems that RDF really needs something as simple as >> rdfs:member. >> >> Please let me know. >> >> Thank you. >> >> Jesse Weaver >> Ph.D. Student, Patroon Fellow >> Tetherless World Constellation >> Rensselaer Polytechnic Institute >> http://www.cs.rpi.edu/~weavej3/> >> >> >> >> > > > ---- > 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.htmlFOAF: http://www.ivan-herman.net/foaf.rdf > > > > > > ===========End of original message text=========== > > > > >
Received on Tuesday, 30 August 2011 11:37:57 UTC