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

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Fri, 30 Mar 2007 11:26:18 +0200
Message-ID: <460CD7BA.4030504@few.vu.nl>
To: "Miles, AJ \(Alistair\)" <A.J.Miles@rl.ac.uk>
CC: public-swd-wg@w3.org, public-esw-thes@w3.org

Hello Alistair,

[I'm slowly reading mails, sorry for the lag]
Thanks for the issue raising work. And yes, what you intended to discuss 
in your first mail is clearer to me now!
I think actually my comments also gave contributions to the issues. I'll 
try to re-work these in the coming days/weeks...

Cheers,

Antoine

>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/BasicLexicalLabelSemantic
>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/ConceptSchemeLabellingInt
>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 Friday, 30 March 2007 09:26:32 GMT

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