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Re: ISSUE-160: Allowing collections in semantic relationships

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Tue, 16 Dec 2008 10:25:54 +0100
Message-ID: <49477422.3010009@few.vu.nl>
To: Leonard Will <L.Will@willpowerinfo.co.uk>
CC: "public-swd-wg@w3.org" <public-swd-wg@w3.org>, "public-esw-thes@w3.org" <public-esw-thes@w3.org>

Hi,

Trying to re-focus the discussion on its original topic
(the other one is also very interesting, maybe more in fact, but there is still boring editorial stuff to do ;-)

> Treating node labels as concepts is not just "not a best practice" - it 
> is logically wrong and misleading.
> 
> If SKOS is just to be used for the generation of hierarchical displays 
> then this fudge can be used, but I thought that it was more than that 
> and was concerned with the accurate representation of semantic 
> relationships

I thought my last paragraph and its "harmful loss of semantic accuracy" would capture that. But I can make the text stronger, if you think this would be appropriate.

Thanks a lot for your help, again,

Antoine


> On Mon, 15 Dec 2008 at 15:08:01, Antoine Isaac <aisaac@few.vu.nl> wrote
>> Hello everyone,
>>
>> I'm coming back to this issue, as I took the following action on me:
>>
>>>    [PENDING] ACTION: Antoine to write something in Primer wrt. ISSUE 
>>> 160 [recorded in 
>>> [37]http://www.w3.org/2008/12/02-swd-minutes.html#action14]
>>
>> I have come with two paragraphs at the end of this mail, to add at the 
>> end of the section on Collections in the SKOS Primer [1]. I hope that 
>> they capture the main lessons that can be learnt from this very 
>> interesting discussion. Feedback is more than welcome!
>>
>> Note that I would prefer not to mention explicitly Johan and Leonard's 
>> solutions, as I feel they would add much detailed for the Primer, and 
>> maybe also too much BS-8723 oriented. But it's clear they'd be welcome 
>> to appear as best practice notes somewhere...
>>
>> Best,
>>
>> Antoine
>>
>> [1] http://www.w3.org/TR/skos-primer/#seccollections
>>
>> ======== beginning of added paragraphs
>>
>> One may wonder whether using collections is desirable, as they add 
>> complexity to the representations applications have to manipulate. In 
>> fact, for some cases, e.g. when KOS are mainly intended as navigation 
>> hierarchies, it seems more intuitive to represent "node labels" or 
>> "guide terms" as instance of skos:Concept, and to use normal semantic 
>> relationships for linking them to other concepts. Take the following 
>> variant of the "milk" example:
>>
>> ex3:milkBySourceAnimal rdf:type skos:Concept;
>>  skos:prefLabel "milk by source animal"@en;
>>  skos:broader ex3:milk;
>>  skos:narrower ex3:cowMilk;
>>  skos:narrower ex3:goatMilk;
>>  skos:narrower ex3:buffaloMilk.
>>
>> The choice between the two representation options remains open, 
>> depending on the application at hand. Readers should however be aware 
>> that not using collections, even if more intuitive, may result in a 
>> harmful loss of semantic accuracy. For many description applications, 
>> for instance, "node labels" are entities of really specific nature, 
>> and must not be used as object indices alongside "normal" concepts. 
>> Representing them as mere concepts is therefore clearly not a best 
>> practice.
>>
>> ======== end of added paragraphs
>>
> Treating node labels as concepts is not just "not a best practice" - it 
> is logically wrong and misleading.
> 
> If SKOS is just to be used for the generation of hierarchical displays 
> then this fudge can be used, but I thought that it was more than that 
> and was concerned with the accurate representation of semantic 
> relationships - witness the extended discussion of the distinction 
> between "broader" and "broader transitive", for example.
> 
> Doing it properly may be slightly more complicated, but that is because 
> the semantic relationships are more complicated. I don't think you can 
> ignore them. If you just want to generate displays you don't need SKOS 
> at all, you can just use simple tags like BT/NT/RT, which give a much 
> simpler exchange format that has served us well in many applications up 
> to now.
> 
> I'm also concerned that you say that a more complete representation is 
> "maybe also too much BS-8723 oriented". Is that a bad thing? In fact it 
> would be better if it were more ISO 25964 oriented, following the model 
> attached to my message of 4th December, which is a later development of 
> the BS-8723 model and which makes the important distinction between 
> "arrays" and "concept groups".
> 
> I am really keen that if SKOS is to become a de facto standard for the 
> exchange of thesaurus data it should be capable of modelling all the 
> elements of a modern thesaurus that complies with standards. If you 
> don't like our model, please tell us what is wrong with it; if you do, 
> why not use it?
> 
> You did say "feedback is more than welcome"!  :-)
> 
> Leonard
Received on Tuesday, 16 December 2008 09:26:32 GMT

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