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RE: [RDFa] ISSUE-8: RDF containers in RDFa

From: Hausenblas, Michael <michael.hausenblas@joanneum.at>
Date: Thu, 12 Jul 2007 22:35:05 +0200
Message-ID: <768DACDC356ED04EA1F1130F97D2985201211BA2@RZJC2EX.jr1.local>
To: "Ivan Herman" <ivan@w3.org>
Cc: "RDFa" <public-rdf-in-xhtml-tf@w3.org>, "SWD WG" <public-swd-wg@w3.org>


Ivan,

Thanks for your comments and the clarification.
I did not take the RDF semantics into account - mea culpa.
Surely I'll update [1] to reflect the new findings ...

Cheers,
	Michael

[1] ] http://www.w3.org/2006/07/SWD/wiki/RDFa/RDFCoverage

----------------------------------------------------------
 Michael Hausenblas, MSc.
 Institute of Information Systems & Information Management
 JOANNEUM RESEARCH Forschungsgesellschaft mbH
 Steyrergasse 17, A-8010 Graz, AUSTRIA
---------------------------------------------------------- 

> -----Original Message-----
> From: Ivan Herman [mailto:ivan@w3.org] 
> Sent: Thursday, July 12, 2007 12:33 PM
> To: Hausenblas, Michael
> Cc: Ben Adida; RDFa; SWD WG
> Subject: Re: [RDFa] ISSUE-8: RDF containers in RDFa
> 
> 
> 
> Hausenblas, Michael wrote:
> > 
> > Ben,
> > 
> > Did you take into account 'RDF features covered by RDFa 
> (RiR)' [1], yet?
> > I know, the description on this page is a bit terse and might need 
> > some more explanations ...
> > 
> > The main finding of [1] is:
> > 
> > '... the only requirements - stemming directly from  the RDF Graph 
> > Model - are to represent:
> > 
> >   + URIrefs
> >   + bNodes
> >   + literals (incl. XMLLiteral) in the triple form S P O
> > 
> >  all other constructs (as rdf:Seq, or rdf:parseType)  are 
> introduced 
> > by RDF/XML .'
> > 
> > Unfortunately I did not get any feedback if my interpretation is 
> > correct,
> 
> Well, it is not _entirely_ correct
> 
> - The RDFS document[1] introduces the classes and properties 
> used to construct containers and collections (not rdf:li, 
> though, that _is_ an RDF/XML artefact). The definitions in 
> [1] are _not_ dependent on RDF/XML or any other serialization.
> 
> - The RDF Semantics[2] documents does not defines more than a 
> minimal semantics to the container terms (Seq, rdf:_1, etc), 
> defining, eg, the latter to be rdf:Property type. The domain 
> and range of rdf:_1 and the others are simply defined to be 
> rdf:Resource, ie, anything. None of the 'usual' semantics 
> associated to Seq, Alt, etc, are formally defined.
> 
> (Many would like to get those out of RDF altogether because 
> they are ill defined, but there is some history there that we 
> cannot ignore. Note also that rdf:_i brings in a very 
> disagreeable feature to the formal semantics, because the 
> number of terms of the RDF vocabulary becomes
> infinite...)
> 
> - There _is_ a semantics attached to the collection terms in 
> a separate 'Collection' vocabulary[3]. Eg, the range of 
> rdf:rest is defined to be rdf:List, that sort of things. Ie, 
> the documents it produces a more or less controlled and 
> controllable way of constructing, well, collections.
> 
> - RDF/XML introduces syntactic sugar for both collections and 
> containers.
> 
> - Turtle introduces syntactic sugar for collections: (a b c d 
> e). It does not introduce anything similar for containers.
> 
> 
> [1] http://www.w3.org/TR/rdf-schema/
> [2] http://www.w3.org/TR/rdf-mt/#Containers
> [3] http://www.w3.org/TR/rdf-mt/#collections
> 
> 
> > but maybe we can discuss this in the context of ISSUE-8. 
> > 
> > My main point here is: vocabulary as rdf:li, or rdf:Seq stem from 
> > RDF/XML, hence we should contemplate on *IF* and *HOW* to 
> support it.
> > 
> 
> I agree that this background is highly relevant.
> 
> Ivan
> 
> 
> > Cheers,
> > 	Michael
> > 
> > BTW: I get more and more the feeling we focus too much on syntactic
> > sugar 
> >      while not resolving essential issues as bNodes, etc.
> > 
> > [1] http://www.w3.org/2006/07/SWD/wiki/RDFa/RDFCoverage
> > 
> > ----------------------------------------------------------
> >  Michael Hausenblas, MSc.
> >  Institute of Information Systems & Information Management
> >  JOANNEUM RESEARCH Forschungsgesellschaft mbH
> >   
> >  http://www.joanneum.at/iis/
> > ----------------------------------------------------------
> >  
> > 
> >> -----Original Message-----
> >> From: public-swd-wg-request@w3.org 
> >> [mailto:public-swd-wg-request@w3.org] On Behalf Of Ben Adida
> >> Sent: Thursday, July 12, 2007 1:10 AM
> >> To: RDFa; SWD WG
> >> Subject: [RDFa] ISSUE-8: RDF containers in RDFa
> >>
> >>
> >>
> >> Hi all,
> >>
> >> There's one syntax issue we haven't talked about n a while that we
> >> should probably address in *some* form: how to express RDF 
> containers
> >> and/or lists. In particular, how do we indicate a list of 
> >> creators, or a
> >> list of licenses, or a list of authors in a paper.
> >>
> >> I wrote a proposal on RDFa containers a while ago:
> >> http://www.w3.org/2001/sw/BestPractices/HTML/2006-rdfa-containers
> >>
> >> but that assumed we would do RDF Bags and Sequences. I don't 
> >> know yet if
> >> that's what we should support, or if we should just focus on lists,
> >> denoted [a,b,c] in Turtle.
> >>
> >> Input from anyone, in particular the SWD WG, would be very 
> helpful! I
> >> think for XHTML1.1+RDFa, we should do the simplest thing 
> that doesn't
> >> completely prevent us from encoding lists of some kind.
> >>
> >> In terms of implementation, the right direction is likely something
> >> using UL, OL, and LI, possibly involving @href/@resource 
> on the LI, as
> >> we had expected @href everywhere in the original 
> XHTML2-based proposal.
> >>
> >> -Ben
> >>
> >>
> > 
> 
> -- 
> 
> Ivan Herman, W3C Semantic Web Activity Lead
> URL: http://www.w3.org/People/Ivan/
> PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
> 
Received on Thursday, 12 July 2007 20:37:06 GMT

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