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Re: Comments on SKOS namespace change question

From: Sean Bechhofer <sean.bechhofer@manchester.ac.uk>
Date: Wed, 1 Oct 2008 11:47:40 +0100
Message-Id: <DA62EE8C-09C5-4A9D-B7B3-1C9B2D3E56D8@manchester.ac.uk>
Cc: SWD Working SWD <public-swd-wg@w3.org>
To: Tim Berners-Lee <timbl@w3.org>

On 30 Sep 2008, at 20:52, Tim Berners-Lee wrote:

> Reading http://www.w3.org/TR/2008/WD-skos-reference-20080829/ ,
> I sympathize very much with the people who want to keep the  
> namespace the same.
>  We're trying to get critical mass and cutting some of the data off  
> and letting it float away by itself it is costly. I don't generate  
> skos myself, but I have come across it.


Thanks for the comment. I understand and appreciate both sides of the  
argument here. We are somewhat between the devil and the deep blue  
sea and I think will end up upsetting /someone/....

> Some people think it's important. I strongly suggest giving new  
> names (within the same namespace)  to the five things which have  
> changed, especially if they're rather obscure.

The issue here is that one of the changes is to the semantics of  
broader (and narrower). If we change the names of these properties,  
then I think a lot of the benefit of keeping the same namespace is  
lost. To return to my earlier characterisation of the issue [1], the  
two choices are:

*A*/ Keep the existing SKOS namespace

+ Existing legacy data can continue to use vocabulary

- Semantics of the SKOS vocabulary change (e.g. broader),
causing problems with legacy applications.

*C*/ Introduce a new SKOS namespace, without the old
vocabulary. Existing schema remains.

+ We can provide new semantics without implicitly affecting
existing collections or implementations
+ Clear versioning
+ Old vocabulary still has machine readable descriptions

- Legacy collections may need to update.

The question then boils down to whether it is better to live with a  
change in the underlying semantics of a vocabulary which is in use,  
or a change in the namespace -- both of which potentially effect  
legacy collections. I have no strong opinions. We have currently  
chosen C, though I could happily live with A, but speaking  
personally, I have no large scale vocabularies or infrastructure that  
rely on the existing semantics.



[1] http://lists.w3.org/Archives/Public/public-swd-wg/2008Apr/0047.html

Sean Bechhofer
School of Computer Science
University of Manchester
Received on Wednesday, 1 October 2008 10:47:47 UTC

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