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Re: dcterms:creator in RDFa Core 1.1, WD of October 26

From: Thomas Baker <tbaker@tbaker.de>
Date: Wed, 10 Nov 2010 20:31:20 -0500
To: Shane McCarron <shane@aptest.com>
Cc: Toby Inkster <tai@g5n.co.uk>, RDFa Working Group <public-rdfa-wg@w3.org>
Message-ID: <20101111013120.GA3964@octavius>
Hi Shane,

On Wed, Nov 10, 2010 at 07:07:16PM -0600, Shane McCarron wrote:
> As far as I recall (Manu?) we were asked explicitly by the dublin core 
> people 

That was me :-)

>         to use dcterms.  I would be very reluctant to go against their 
> wishes... it's their taxonomy after all.

There are two quite different issues here which may be getting

-- Whether to use the "dc:" prefix for "http://purl.org/dc/terms/".
   At some point, I wrote to the list pointing
   out that "dc:" is used quite extensively for
   "http://purl.org/dc/elements/1.1/", and I suggested that, to
   avoid confusion, "http://purl.org/dc/terms/" be associated with 
   the prefix "dcterms:".

-- Whether to use DC properties in their rangeless
   /elements/1.1/ variants or in their "ranged" /terms/
   variants -- the issue I discuss below.  DCMI has
   generally been encouraging the correct use of properties 
   from the /terms/ namespace, but is this really the best
   choice for RDFa?  Jeni Tennison's point makes me 
   wonder.  DCMI does offer both, so the RDFa WG 
   really does have a choice.


> On 11/10/2010 6:50 PM, Thomas Baker wrote:
> >On Wed, Nov 10, 2010 at 10:11:22PM +0000, Toby Inkster wrote:
> >>>Some of the examples in [1] generate triples such as:
> >>>
> >>>     <>  foaf:primaryTopic<#bbq>  .
> >>>     <>  dcterms:creator "Jo" .
> >>>
> >>>However, http://purl.org/dc/terms/creator has a range of
> >>>dcterms:Agent. Using dc:creator would not be incorrect because
> >>>http://purl.org/dc/elements/1.1/creator has no specified range
> >>>(or rather, by default, rdfs:Resource).
> >>This seems to me to be a conflict between:
> >>
> >>1. the desire to use the latest and greatest version of Dublin Core; and
> >>2. the desire to use a literal object so that the example includes both
> >>a literal and a URI.
> >>
> >>Perhaps something like dcterms:modified could be used in the example
> >>instead of dcterms:creator, as that has a literal object?
> >If an example using literal object is needed at that point in
> >the spec, that would of course work.  However, that does not
> >address the question of best practice regarding the fifteen
> >core properties in their /terms/ and /elements/1.1/ variants.
> >
> >DCMI assigned ranges in order to conform to emerging notions of
> >best practice.  However, it did not "deprecate" the rangeless
> >properties because they had at that point already been used
> >very extensively in Semantic Web data -- with both literal
> >and non-literal objects.  By coining "parallel" properties,
> >DCMI offered data providers a choice.
> >
> >DCMI has been "gently promoting" the /terms/ variants for being
> >"more precise" and for helping data consumers by making the
> >data more consistent.  However, I have been getting feedback
> >that "rangeless" properties are actually useful, which
> >Jeni Tennison's point seems to reinforce.
> >
> >Specifically with regard to Dublin Core properties, it is clear
> >that the distinction between dc:creator and dcterms:creator is
> >not widely understood.  If the dcterms: variants are promoted
> >(e.g., in the RDFa specs), what is the risk that they will
> >be used incorrectly?  If the risk is high, should we not then
> >promote the dc: properties?
> >
> >More generally, what is the message for vocabulary developers
> >today?  Are there uses for which the right design decision is
> >to err on the side of underspecification?  This is a general
> >question of best practice for Semantic Web, but Jeni is raising
> >it specifically for the case of RDFa.  If not on this list,
> >where might we have this more general discussion?
> >
> >Tom
> >
> -- 
> Shane P. McCarron                          Phone: +1 763 786-8160 x120
> Managing Director                            Fax: +1 763 786-8180
> ApTest Minnesota                            Inet: shane@aptest.com

Tom Baker <tbaker@tbaker.de>
Received on Thursday, 11 November 2010 01:31:51 UTC

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