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Re: SKOS Comment (Reference WD June 2008) - broaderTransitive < broader, narrowerTransitive < narrower

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Sat, 02 Aug 2008 15:51:56 +0200
Message-ID: <4894667C.40208@few.vu.nl>
To: public-esw-thes@w3.org
CC: public-swd-wg@w3.org

Hi Leonard

>> "The Hierarchical Relationship" is transitive across the subtypes 
>> within the domain of Knowledge Organization Systems;  however the 
>> subtype of relationship is lost.
> Why then has SKOS introduced the idea that "broader" is not 
> necessarily transitive, requiring the introduction of a different 
> relationship "broaderTransitive"?
>> If a current KOS defines a relationship  between terms where A *R* B 
>> and B *
>> R* C , but not A *R* C,   *R* *doesn't* correspond to BT.
>> By definition, the relationship is an associative one.  The correct 
>> way to
>> map these relationships into SKOS is as a (possible subrole of)  
>> *related*.
> Are you saying here that if a relationship is not transitive, it 
> should not be expressed as "broader"? I.e. that SKOS does not need to 
> introduce "broaderTransitive" because "broader" is by definition 
> transitive and if it is not the relationship should be associative 
> rather than hierarchical?
> This is on the assumption that SKOS is modelling thesauri that conform 
> to standards, which is what I think it should do. Some existing KOSs 
> look like thesauri but have incorrect relationships - SKOS can encode 
> these as though the relationships were correct, but users would have 
> to realise that inferences cannot be drawn from them with any confidence.

Again, if we say that skos:broader is transitive in the SKOS semantics, 
then we cannot have user "realize hat inferences cannot be drawn from 
them with any confidence". *If it is in the semantics, it can be 
inferred with confidence*. That's all, and I really want to make that 
point clear.

That's why we de-coupled what is not controversial ("this broader was 
asserted in that thesaurus, and we publisher of the thesaurus want you 
to know it") from what is useful but should not mess up with initial 
assertions (broaderTransitive)

> The hierarchies of a classification scheme, which represent 
> combination of concepts as well as just subordination of concepts, are 
> not at present within the scope of SKOS, so it is inappropriate to try 
> to use SKOS to model them until it is extended.

We might disapprove here. I don't think it is useful to limit the scope 
of SKOS that way. Actually our use cases and requirements [3] hint at 
varied cases, such as product classifications, classification schemes...

Indeed the STITCH project we have worked on SKOSifying Iconclass and 
this has been taken on by people even closer to the vocabulary than we 
are [1]
And I'm happy to see that people are considering using SKOS for 
publishing DDC information [2]. I've not read the paper, but even if 
that proves not to be 100% appropriate, and, as you say, would require 
some extensions for specific KOS area, it still proves that there is 
value in trying to have a backbone model with broader scope.
Otherwise, to bounce back on the other running discussion, SKOS would be 
more of a thesaurus interchange format, not much different from the new 
British Standard format for this.

Note that even if SKOS was restricted on thesauri, and if there was a 
significant proportion of thesauri for which Simon's assertions do not 
hold, then we could not define broader as transitive, for the reason 
mentioned in the first part of my answer.


[1] http://blog.pos.thum.us/2008/03/04/skos-support-for-iconclass/
[2] http://www.ebsi.umontreal.ca/isko2008/documents/programme_OCLC.pdf
[3] http://www.w3.org/TR/skos-ucr/
Received on Saturday, 2 August 2008 13:52:30 UTC

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