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Re: How to distinguish unique and non-unique prefLabels?

From: Jakob Voss <jakob.voss@gbv.de>
Date: Thu, 13 Jan 2011 09:35:31 +0100
Message-ID: <4D2EB953.4000500@gbv.de>
CC: public-esw-thes@w3.org
Simon wrote:

> A skos:Concept is not required  to have a prefLabel (SKOS §5.6.4); in
> fact, a Concept is not required to have any labels at all.  There are no
> cardinality constraints on the range of  prefLabel at all.

Yes, but at the same time it does not require prefLabels to be unique 
per concept scheme. I guess I need to do one of both (concepts without 
prefLabel or non-unique prefLabels), but I'd choose the "most common" 
variant.

> It is very useful to be able to have anonymous concepts, as  Jakob
> notes.  Anonymous concepts give very simple solutions to two of the
> simpler cases of compound terms; where a term is split into "USE A or
> B", and when a term is split into "USE A and B"

That is another good use-case of anonymous concepts.

> The absence of a preferred label can in fact be a good indicator that a
> concept is not authorized for use (since it would not be possible to use
> it in printed form). References to concepts with no preferredLabel can
> indicate a need to update the reference - automatically for
> conjunctions; intelligently in the case of disjunctions.

But you *can* get a printed form, *if* the concept has some other kind 
of title (unique rdfs:label or unique dc:title per concept). If "absence 
of prefLabel" is interpreted as indicator for non-authorized use, I 
would better not choose dc:title for the non-unique labels of my 
classification. I'd prefer not to propagate such an interpretation. 
Instead we could agree on the following rule:

1. To determine the label for display of a concept, use prefLabel.
2. If there is no prefLabel, use dc:title
3. If there is no dc:title, use rdfs:label

The disadvantage of rdfs:label is, that in many cases it is not unique 
per label, so you will choose a *random* rdfs:label from the set of all
rdfs:label properties. Maybe we can improve this rule-of-thumb.

Jakob

-- 
Jakob Voß <jakob.voss@gbv.de>, skype: nichtich
Verbundzentrale des GBV (VZG) / Common Library Network
Platz der Goettinger Sieben 1, 37073 Göttingen, Germany
+49 (0)551 39-10242, http://www.gbv.de
Received on Thursday, 13 January 2011 08:36:48 UTC

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