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

From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
Date: Mon, 19 Mar 2007 14:41:53 -0000
Message-ID: <677CE4DD24B12C4B9FA138534E29FB1D0285A1CB@exchange11.fed.cclrc.ac.uk>
To: "Antoine Isaac" <aisaac@few.vu.nl>
Cc: <public-swd-wg@w3.org>, <public-esw-thes@w3.org>

... I.e. ISSUE-31 arises whenever you use skos:prefLabel, skos:altLabel
and skos:hiddenLabel. ISSUE-32 only arises when you use skos:inScheme as
well.

Cheers,

Al.

--
Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
Chilton
Didcot
Oxfordshire OX11 0QX
United Kingdom
Web: http://purl.org/net/aliman
Email: a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440  

> -----Original Message-----
> From: public-swd-wg-request@w3.org 
> [mailto:public-swd-wg-request@w3.org] On Behalf Of Miles, AJ 
> (Alistair)
> Sent: 19 March 2007 14:27
> To: Antoine Isaac
> Cc: public-swd-wg@w3.org; public-esw-thes@w3.org
> Subject: RE: [SKOS] Possible issue: Uniqueness of 
> skos:prefLabel [was Re: [SKOS] inconsistency between Guide 
> and Specification
> 
> 
> Hi Antoine,
> 
> Whenever I say "semantics" I mean formal semantics specified 
> using model
> theory, see:
> 
> [1] http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#prelim
> 
> I think you have slightly misunderstood my intention. Let me try to
> explain a different way, raising some issues in the issue 
> tracker at the
> same time ...
> 
>  - Issue: "BasicLexicalLabelSemantics"
> 
> Can a resource have two "preferred lexical labels"? Can a 
> lexical label
> be both
> "preferred" and "alternative" for the same resource? If a 
> lexical label
> is
> "hidden", can it also be "preferred" or "alternative" for the same
> resource?
> 
> See:
> 
>  [2]
> <http://www.w3.org/2006/07/SWD/wiki/SkosDesign/BasicLexicalLab
> elSemantic
> s>
>  [3] <http://www.w3.org/2006/07/SWD/track/issues/31>
> 
>  - Issue: "ConceptSchemeLabellingInteractions"
> 
> Can two different concepts in the same concept scheme have any lexical
> labels in common?
> 
> I.e. can two different concepts in the same concept scheme 
> both have the
> same preferred lexical label? Can two different concepts in the same
> concept scheme both have the same alternative lexical label? Can a
> lexical label be preferred for one concept and alternative for a
> different concept in the same concept scheme? Can a lexical label be
> hidden for one concept and either preferred or alternative for a
> different concept in the same concept scheme?
> 
> See:
> 
>  [4]
> <http://www.w3.org/2006/07/SWD/wiki/SkosDesign/ConceptSchemeLa
> bellingInt
> eractions>
>  [5] <http://www.w3.org/2006/07/SWD/track/issues/32>
> 
> Does that clarify?
> 
> Cheers,
> 
> Al.
> 
> --
> Alistair Miles
> Research Associate
> CCLRC - Rutherford Appleton Laboratory
> Building R1 Room 1.60
> Fermi Avenue
> Chilton
> Didcot
> Oxfordshire OX11 0QX
> United Kingdom
> Web: http://purl.org/net/aliman
> Email: a.j.miles@rl.ac.uk
> Tel: +44 (0)1235 445440  
> 
> > -----Original Message-----
> > From: public-swd-wg-request@w3.org 
> > [mailto:public-swd-wg-request@w3.org] On Behalf Of Antoine Isaac
> > Sent: 02 March 2007 10:47
> > To: Miles, AJ (Alistair)
> > Cc: public-swd-wg@w3.org; public-esw-thes@w3.org
> > Subject: Re: [SKOS] Possible issue: Uniqueness of 
> > skos:prefLabel [was Re: [SKOS] inconsistency between Guide 
> > and Specification
> > 
> > 
> > Hi Alistair
> > 
> > Thanks for the long mail. I think I got the idea, but the 
> > naming of the issues is confusing (perhaps because of the 
> > many different interpretation of "semantics"), and the use of 
> > examples too. To me the 'content' of the conditions mentioned 
> > in issue 1 should be discussed in issue 2, while (correct me 
> > if I'm wrong) issue 1 is just about the question of formally 
> > encoding these axioms in a specific language or not, and 
> > decide (or not) to use them as a basis for quality checking 
> > procedures.
> > 
> > Shortly, I want to make three remarks on what in my eyes 
> > should be in issue 2, that is the 'content' of the conditions
> > 
> > >The first of these is that, intuitively, only one label (per 
> > language 
> > >per script) can be "preferred". In other words, it does not 
> > make sense 
> > >for two things to both be "preferred".
> > >
> > >The second of these is that, intuitively, it does not make 
> > sense for a 
> > >label to be both "preferred" and "alternative"; or both 
> > "preferred" and 
> > >"hidden"; or both "alternative" and "hidden".
> > >  
> > >
> > I completely agree with the beginning, less with the 
> > conditions on "hidden". What if a typo on a term for a 
> > concept (which could be encoded as hidden, if I understood 
> > well this property) corresponds to the preferred term of 
> > another concept? I agree this is borderline, but if someone 
> > has met this situation it is time to say it before we 
> > register the condition as valid!
> > 
> > >
> > >In some types of controlled vocabulary, it may be entirely 
> > reasonable 
> > >for two concepts in the same scheme to have the same 
> > preferred lexical 
> > >label (in some language/script). This is the case, for 
> > example, in some 
> > >classification schemes (where two "classes" may have the same 
> > >"caption") and corporate taxonomies (where two "nodes" may 
> have the 
> > >same "label"), in which case either the notation or the 
> > context is used 
> > >to disambiguate meaning.
> > >  
> > >
> > True. It might also be the case in multilingual thesauri 
> > having one 'reference' language, in which the prefLabels are 
> > unambiguous, and 'translations' which are less constrained.
> > Notice then that it does not remove completely the 
> > constraint, which should read like "there is at least one 
> > language in which the prefLabel is unambiguous" (which is btw 
> > the case is many classification schemes, in which the 
> > 'artificial' notation language plays this role)
> > 
> > ><snip> For this reason, I agree with Guus that these two 
> > sentences be 
> > >dropped from all future SKOS specifications, and that no formal 
> > >conditions should be placed on the use of the SKOS lexical 
> labeling 
> > >properties in conjunction with the SKOS concept scheme constructs 
> > >(currently skos:inScheme and skos:ConceptScheme).
> > >
> > >However, for a SKOS concept scheme to be *usable* as a 
> > thesaurus (i.e.
> > >compatible with software following the ISO2788 standard) some 
> > >restrictions must be observed on the use of these properties in 
> > >conjunction.
> > >
> > >
> > >
> > >Because of the importance of being able to identify 
> > compatibility with 
> > >existing thesaurus software and standards, I would like to 
> > argue that 
> > >we specify, informally, a set of restrictions which may be 
> > *optionally* 
> > >applied in order to detect thesaurus incompatibility. I.e. these 
> > >restrictions *would not* be part of the formal semantics of SKOS.
> > >  
> > >
> > I agree with the fact that even my "adapted" condition above 
> > could be restricted so such a 'best practice for thesauri' 
> > informal and optional approach.
> > I would however say that I think this condition apply to a 
> > very wide range of concept schemes, if not an overwhelming 
> > majority. The only one I can think of at the moment are 
> > perhaps the web taxonomies such as Yahoo. And I think none of 
> > the use cases gathered for SKOS has this ambiguity case. Once 
> > again, this is a call for (counter-)examples!
> > 
> > >These restrictions can be stated informally, with examples 
> of SPARQL 
> > >queries that could be used to detect incompatibilities. Expressing 
> > >these restrictions formally is complicated and unnecessary.
> > >  
> > >
> > Of course if no constraint is kept in the end (that is, Guus' 
> > proposal) I fully agree with this policy.
> > 
> > Cheers,
> > 
> > Antoine
> > 
> > >  
> > >
> > >>-----Original Message-----
> > >>From: public-swd-wg-request@w3.org
> > >>    
> > >>
> > >[mailto:public-swd-wg-request@w3.org]
> > >  
> > >
> > >>On Behalf Of Guus Schreiber
> > >>Sent: 27 February 2007 12:01
> > >>To: public-swd-wg@w3.org
> > >>Cc: SWD WG
> > >>Subject: [SKOS] Possible issue: Uniqueness of 
> > skos:prefLabel [was Re:
> > >>[SKOS] inconsistency between Guide and Specification
> > >>
> > >>
> > >>
> > >>
> > >>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 De 
> Boelelaan 1081a, 
> > >>1081 HV Amsterdam, The Netherlands
> > >>T: +31 20 598 7739/7718; F: +31 84 712 1446 Home page: 
> > >>http://www.cs.vu.nl/~guus/
> > >>    
> > >>
> > >
> > >
> > >
> > >  
> > >
> > 
> > 
> > 
> 
> 
Received on Monday, 19 March 2007 14:41:59 GMT

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