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Re: Use case : issues with unicity of skos:prefLabel

From: Jakob Voss <jakob.voss@gbv.de>
Date: Thu, 19 Oct 2006 15:49:59 +0200
Message-ID: <45378287.8080307@gbv.de>
To: public-esw-thes@w3.org

Hi Bernard!

Thanks for pointing us to another special controlled vocabulary we have
to deal with! You wrote:

> the same term can be used several times with different semantics, the 
> disambiguation being made by its position in the broader-narrower
> hierarchy - which is always displayed in any index publication,
> so the term is never used "out of context".

This sound similar to a classification where same class names may occur
at different positions for different classes. But in a classification
there are normally notation to identify a class.

I talked with Alistair about the need of captions and notations in SKOS.
There is definitely the need for a new property skos:notation. For
captions he suggested to weaken the uniqueness requirement of
skos:prefLabel. Is your concept scheme a strict thesaurus? If this is
not the case then prefLabel does not have to uniquely identify a concept.

> For example you will have that kind of hierarchy in the index (the
> actual terms are in french ...)
> Civil procedure
>    General principles
>        Procedure action
>            Notification
> It's clear that "Notification" is likely to be not unique in the index.

But you can still use skos:prefLabel as described above.

> So if we want a unique identifying name for each index entry, the
> context has to be included. The solution we have come up to, is to mark
> as "context terms" the terms which disambiguate their descendants . In
> this case "Civil procedure" and "Procedure action" are declared as
> context terms, but "General principles" is not (it's useless for
> disambiguation). Hence the identifying string of Notification should be
> something like : "Civil procedure: Procedure action: Notification". 

So you build another unique identifying label - what is the purpose?

1.) Do you want this label for prefered display? Then use skos:prefLabel
and "Notification" is just an skos:altLabel.

2.) Do you want this label only to use when you need to uniquely
identify concepts? Then use skos:notation like in a classification
scheme. By the way many notations in classification schemes also include
hierarchical information (if you know how to decode them).

> A kind of post-coordination based on hierarchy, if you like.

Well ....no.

> My question is : if we want to represent that in SKOS, what should be
> the practice?

We need a new property skos:notation or skos:notationLabel.

> Using "Civil procedure: Procedure action: Notification" as
> skos:prefLabel seems unavoidable if one wants unicity of prefLabel,

The unicity of prefLabel is only needed for thesauri. Because SKOS has
been mainly used for thesauri we thought that prefLabel always needs to
be unique in a ConceptScheme. But the uniqueness is only a property of a
ConceptScheme that needs to be fullfilled in order to use the
ConceptScheme as a thesaurus.

> In topic maps (and in Mondeca ITM too) we have the cool notion of 
> "display Name". Would not be skos:displayLabel a good idea in that case?
> I vaguely remember this property has been discussed at some point. Then
> we would have
> skos:prefLabel              Civil procedure: Procedure action: Notification
> skos:displayLabel          Notification
> skos:altLabel                 Procedure notification

With skos:notation we would have:

skos:prefLabel  "Notification" .
skos:notation   "Civil procedure: Procedure action: Notification" .
skos:altLabel   "Procedure notification" .

Received on Thursday, 19 October 2006 13:49:08 UTC

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