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Re: [POWDER] About describedby

From: Phil Archer <phil@philarcher.org>
Date: Tue, 02 Dec 2008 09:55:28 +0000
Message-ID: <49350610.1030309@philarcher.org>
To: Andrea Perego <andrea.perego@uninsubria.it>, Public POWDER <public-powderwg@w3.org>

Thanks for this Andrea - it gives me a chance to set things out clearly 
(which I should have done for yesterday's telecon).

Andrea Perego wrote:
> Hi, Phil.
> Could you please remind me why we should drop the range specification
> for describedby? Is it about using it in ATOM?

No, it's not related to it being used for ATOM as such. In my original 
e-mail to IANA, included in the mail at [1], it says:

"The relationship A 'describedby' B does not imply that B is a POWDER 
file (the MIME type does that), simply that B provides a description of 
A. The representation returned from A and B is not constrained by the 

Following feedback from Julian Reschke (and a chat on the phone with 
him) I've proposed some amendments to the DR doc reported to the group 
at [2] with the relevant changes visible temporarily at [3]. It looks 
like a big re-write of that section on linkage but it isn't. All I've 
done is to re-order the sections a little and shown how link @rel 
elements can be used in ATOM. However, when the wdrs:describedby 
property is introduced [4] I've suggested that we say:

The meaning of wdrs:describedby is identical to the describedby 
relationship type defined above so that:




For this to be true, bearing in mind the requested registration of 
describedby, we need to drop the range constraint.

The upside of doing this is that we keep the @rel type and the RDF 
vocabulary term consistent with each other. In the RDFa example (now 
numbered 4-3) the type attribute is still there to hint that the target 
of the link is a POWDER document. The downside is that this is not true 
for the second RDFa example, now numbered 4-4.

Given all that - do you agree that we can drop the range constraint? If 
not, then I can only suggest that we should define a different, 
POWDER-specific, vocabulary term for use in RDFa - but then I fear that 
might be confusing since RDFa allows @rel types [5] and it's going to 
get messy.


[1] http://lists.w3.org/Archives/Public/public-powderwg/2008Nov/0016.html	
[2] http://lists.w3.org/Archives/Public/public-powderwg/2008Nov/0021.html
[3] http://philarcher.org/powder/20081124.html#assoc
[4] http://philarcher.org/powder/20081124.html#semlink
[5] http://www.w3.org/TR/rdfa-syntax/#rdfa-attributes


Phil Archer
w. http://philarcher.org/
Received on Tuesday, 2 December 2008 09:56:14 UTC

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