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Re: [SKOS] About notations and datatypes (was Re: Comments on Vocabularies document, v 1.15)

From: Alistair Miles <alistair.miles@zoo.ox.ac.uk>
Date: Thu, 9 Oct 2008 12:39:09 +0100
To: Norman Gray <norman@astro.gla.ac.uk>
Cc: Antoine Isaac <aisaac@few.vu.nl>, SWD WG <public-swd-wg@w3.org>, SKOS <public-esw-thes@w3.org>, Alasdair Gray <agray@dcs.gla.ac.uk>
Message-ID: <20081009113908.GF19524@skiathos>

Hi Norman,

Yes we've had a number of comments regarding the notations
feature. Most of the comments focus on problems regarding the use of
custom datatypes, and one option for us is to consider relaxing the
usage convention for typed literals as the object of skos:notation
triples. However I see from the first example in [1] that you don't
use datatypes anyway, so this would not be a problem for you. But
however this goes, I think it is very unlikely that the skos:notation
property would be dropped altogether.

End Dec 2008 is still the target for full Rec...

Cheers,

Alistair.

[1] http://www.ivoa.net/Documents/PR/Semantics/Vocabularies-20080912.html

On Wed, Oct 08, 2008 at 12:17:13PM +0100, Norman Gray wrote:
>
>
> Antoine, hello.
>
> On 2008 Oct 4, at 14:26, Antoine Isaac wrote:
>
>>> Now, I'm not a real expert in RDF datatypes, it would be great if  
>>> someone on the list could validate your approach with more  
>>> certainty. Especially, if it is something that shall be encouraged  
>>> or discouraged (my two cents is that it should be encouraged if we  
>>> want people to use skos:notation). Jeremy's opinion would be useful, 
>>> as he co-authored [3]!
>
> Thanks -- Jeremy's opinion would indeed be valuable here.
>
>
>
> A slightly broader point:  We were hoping to get the Vocabularies  
> document to an IVOA Recommendation within the next month or so, thus  
> before the SKOS document itself was due to become a W3C REC.  We  
> justified this questionable practice to ourselves because we were using 
> only core features of SKOS, unlikely to change between the current drafts 
> and the REC.  However I see from the list of issues which have appeared 
> on the SWD list, that things like skos:notation are still to some extent 
> contestable [1].  This is making me worry that perhaps we should hold 
> back after all.
>
> Do you think that there is likely to be significant change to the sort  
> of core SKOS aspects we've refererred to in our document?  Or, a related 
> question, is end-December 2008 still the expected date for SKOS to become 
> a REC?  (If so, it's close enough that the argument for going ahead out 
> of sync starts to evaporate).
>
> Best wishes,
>
> Norman
>
>
> [1] http://www.w3.org/2006/07/SWD/track/issues/184
>
>
>
>
>
> On 2008 Oct 4, at 14:26, Antoine Isaac wrote:
>
>>
>> Hello Norman,
>>
>> Glad that my comments on IVOA vocabularies document could help a bit!
>>
>> About the following issue:
>>
>>>
>>>> - I think your proposed example for notations is not compliant  
>>>> with what the SKOS Reference and Primer say about these [1,2].  
>>>> skos:notation should be used with literals with a specific  
>>>> datatype, as in
>>>> ex:udc512 skos:prefLabel "Algebra" ;
>>>> skos:notation "512"^^ex:myUDCNotationDatatype .
>>>> (and yes, it is not a very simple representation. Which is why we  
>>>> left the "private use tags with skos:prefLabel" option 
>>>> available...)
>>>
>>> Ah, we hadn't spotted that.  Given that a vocabulary and its  
>>> notations are defined in a PDF document http://foo/bar.pdf (which is 
>>> distinct from the current document), I suppose I can refer to this as 
>>> follows:
>>>
>>> <#concept>
>>>  skos:notation "1.2.3"^^<#notation> .
>>> <#notation>
>>>  dc:description "The notation is defined in the document 
>>> http://foo/bar.pdf" .
>>>
>>> Would that be correct?  It appears to be consistent with the text in 
>>> SKOS Reference section 6.5.
>>>
>>> In this context, I can see little benefit in creating an XSchema  
>>> datatype, and requiring something like that would increase the  
>>> complication of the Recommendation we're writing.
>>
>> I would be rather sceptical about defining an explicit XML datatype,  
>> too.
>> Honnestly I've always been sceptical about the skos:notation stuff,  
>> because it seemed to be forcing people to make too complex things.
>> But in fact if your suggestion is correct (and it seems to be!) that  
>> would give a good balance, anchoring a string to a well-identified and 
>> accessible notation-defining space and still not defining this space 
>> formally. I'd be tempted to mention more explicitly this practice in 
>> the Primer, also (in which case it would be our turn to be thankful to 
>> you ;-)
>>
>> Now, I'm not a real expert in RDF datatypes, it would be great if  
>> someone on the list could validate your approach with more certainty. 
>> Especially, if it is something that shall be encouraged or discouraged 
>> (my two cents is that it should be encouraged if we want people to use 
>> skos:notation). Jeremy's opinion would be useful, as he co-authored 
>> [3]!
>>
>> Cheers,
>>
>> Antoine
>>
>> [3] http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314
>>
>>
>>
>>>
>>> Thanks again for the comments.  Best wishes,
>>>
>>> Norman
>>>
>>>
>>
>>
>>
>
> -- 
> Norman Gray  :  http://nxg.me.uk
> Dept Physics and Astronomy, University of Leicester
>
>

-- 
Alistair Miles
Senior Computing Officer
Image Bioinformatics Research Group
Department of Zoology
The Tinbergen Building
University of Oxford
South Parks Road
Oxford
OX1 3PS
United Kingdom
Web: http://purl.org/net/aliman
Email: alistair.miles@zoo.ox.ac.uk
Tel: +44 (0)1865 281993
Received on Thursday, 9 October 2008 11:39:51 GMT

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