W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > October 2006

Re: better support for bnodes

From: Ivan Herman <ivan@w3.org>
Date: Fri, 20 Oct 2006 13:10:24 +0200
Message-ID: <4538AEA0.8090608@w3.org>
To: Ben Adida <ben@mit.edu>
CC: public-rdf-in-xhtml-tf@w3.org


Ben Adida wrote:
> 
> 
>>2- a side issue, which goes actually against the example I gave.
>>Although the usage for <ul><ol><nl> for Bag/Seq/Alt seems to be an
>>obvious choice (and works well), what I miss is the encoding of lists
>>(maybe that was already discussed elsewhere, sorry if I missed it). As
>>you know, the Bag/Seq/Alt are not really part of the core semantics of
>>RDF(S), they are 'added on' features, so to say. Moreover, there are
>>lots of discussions about removing them from RDF altogether (the fact
>>that the _1, etc, bring in a potentially infinite amount of resources
>>was a significant problem on the theoretical side, for example). Lists
>>are much more important, they are semantically more stable. As such, I
>>would prefer the <ul>...</ul> to map on lists by default (and some extra
>>tweaks should be done for the containers). As I said, maybe this is
>>already settled, but I have not seen it.
> 
> 
> I don't think we have an encoding of lists... though if RDF containers
> are going away, then maybe we need to rethink what UL and OL map to. Can
> you point us to the right RDF specs for lists and what the current
> thinking is?
> 


I guess

http://www.w3.org/TR/rdf-primer/#collections

should do for the definition. If you have ever done some lisp, then it
is what you have...

As for what the future holds about containers vs collections: it is of
course difficult to say. I think the main problem is that the
'semantics' for Seq/Alt/Bag is, well, not semantics in the sense of RDF
semantics at all mathematically, just a set of conventions, whereas
collections have a clear structure. Also, as I said above, the _1, etc,
have created quite a difficulty in the mathematical proofs of various
things.

Whether a future release will make these deprecated or not, I simply do
not know. My *personal* feeling is that it is too late for that, there
are too much data out there that already use them (eg, XMP). But, for
example, if you look at the RDF definition of OWL or (I think) SKOS, you
will see that none of those use these, they use collections instead. Ie,
you will see vocabularies coming up that do use collections; therefore,
being able to express those in RDFa is important.

Ivan-the-headache-creator-for-Ben:-)





> -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 Friday, 20 October 2006 11:11:59 GMT

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