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Re: [SKOS] Possible issue: Uniqueness of skos:prefLabel [was Re: [SKOS] inconsistency between Guide and Specification

From: Guus Schreiber <schreiber@cs.vu.nl>
Date: Tue, 27 Feb 2007 14:56:46 +0100
Message-ID: <45E4389E.7080906@cs.vu.nl>
To: Antoine Isaac <aisaac@few.vu.nl>
CC: public-swd-wg@w3.org

Antoine Isaac wrote:
> Hi Guus,
> I'm not really convinced by this argument, for two reasons:
> - relevance to domain practice: even if a motivation for the constraint 
> in ISO and other thesaurus modelling approaches (especially term-based 
> ones, which are still encountered in many situations) was this reference 
> uniqueness, there are also strong normalization issues underway. People 
> managing thesauri are often spending a lot of time distilling *the* term 
> that embodies the concept in the best way. And while standard database 
> have been allowing for unique keys for decades, they still keep to this 
> constraint on the labels.

And nothing prevents them from keeping on doing 
so. My point is that I see no reason to make this 
customary practice a hard constraint for all users 
of SKOS. Why would we want to prevent some 
thesaurus builder,who wants to have multiple 
preferred labels in the same language, to use SKOS?

Anyway. the is no way to express this cardinality 
constraint in RDF/OWL while taking the 
multi-lingual aspect into account .

> - coherence of the model: if we remove all the cardinality constraints, 
> what would be the indended meaning of a preferred label? This might 
> sound a rather stupid argument, but I really cannot see what makes a 
> label 'preferred' if its associated concept has two such labels.

I seem to remember a use case from Alan at the ftf 
(although I can't find it in the minutes) where he 
wanted to be able to define that both the full 
term and its acronym (?) are preferred labels.


> Cheers,
> Antoine
>> Guus Schreiber wrote:
>>> While trying to write down a resolution for the relationship between 
>>> labels I found:
>>> in the Core Guide, section on Multilingual La belling [1]
>>> [[
>>>   It is recommended that no two concepts in the same concept scheme 
>>> be given the same
>>>   preferred lexical label in any given language.
>>> ]]
>>> in the Core Specification, table of prefLabel [2]
>>> [[
>>>   No two concepts in the same concept scheme may have the same value 
>>> for skos:prefLabel
>>>   in a given language.
>>> ]]
>> I see no need for placing a constraint on the uniqueness of 
>> skos:prefLabel. While some/many vocabularies will actually abide to 
>> this, the URI of the concept the label is related already ensures 
>> uniqueness of the concept being identified (which I assume was the 
>> reason for including this constraint in the ISO spec). I also suggest 
>> that there is no need to place cardinality constraints on skos:prefLabel.
>> The underlying rationale is that we should refrain from overcommiting 
>> the SKOS specification when there is no clear need.
>> I want to raise this as an issue and propose the above as a resolution.
>>> The weaker constraint in the Guide makes sense to me. I will most 
>>> likely propose an even weaker version in my resolution.
>>> Guus
>>> [1] http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102/#secmulti
>>> [2] http://www.w3.org/TR/swbp-skos-core-spec/#prefLabel

Vrije Universiteit Amsterdam, Computer Science
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Received on Tuesday, 27 February 2007 13:57:06 UTC

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