Re: Relationships involving collections

Hi Jakob,

Jakob Voss wrote:
>
> Hi Alasdair!
>
> You wrote:
>
>> With regard to the latest skos reference working draft, how should 
>> mappings between vocabularies that involve collections be performed?
>>
>> In the astronomy vocabularies that I have been working with, I have 
>> come across several instances where I either need to directly relate 
>> 2 collections or a collection with a concept. One such example is for 
>> relating the vocabulary of astronomy and astrophysics journal 
>> keywords (A&A) [1] with the international astronomical union 
>> thesaurus (IAUT) [2]. Below are brief snippets of the two vocabularies.
>>
>> A&A
>> Concept: "Sources as function of wavelength"
>>  NT Collection: "Gamma Rays"
>>    NT Concept: "Gamma ray bursts"
>>       Concept: "Gamma ray observations"
>>       Concept: "Gamma ray theory"
>
> That's in RDF:
>
> aa:1 a skos:Concept ;
>  skos:prefLabel "Sources as function of wavelength" ;
>  skos:narrower aa:2 .
>
> aa:2 a skos:Collection ; rdfs:label "Gamma Rays" ;
>  skos:member aa:3 ;
>  skos:member aa:4 ;
>  skos:member aa:5 .
>
> aa:3 a skos:Concept ; skos:prefLabel "Gamma ray bursts" .
> aa:4 a skos:Concept ; skos:prefLabel "Gamma ray observations" .
> aa:5 a skos:Concept ; skos:prefLabel "Gamma ray theory" .
That is what I was intending. However, this is *not* compliant with the 
latest working draft [4] as skos:narrower cannot be applied to 
collections. In fact, this raises the question, how do you state where a 
collection fits within a hierarchy? All the examples of 
collections/arrays show them within a hierarchy but by my understanding 
this can no longer be stated in SKOS.
>
>> IAUT
>> Concept: "Radiation"
>>  NT Concept: "Gamma rays"
>
> That's in RDF:
>
> iaut:1 a skos:Concept ; skos:prefLabel "Radiation" ;
>   skos:narrower iaut:2 .
> iaut:2 a skos:Concept ; skos:prefLabel "Gamma rays" .
Again, that is what I was intending.
>
>> I would like to assert
>> A&A:"Gamma Rays" skos:exactMatch IAUT:"Gamma rays"
>
> You try to assert
>
> aa:2 skos:exactMatch iaut:2 .
>
> But why don't you assert the following:
>
> iaut:2
>   skos:narrowMatch aa:3 ;
>   skos:narrowMatch aa:4 ;
>   skos:narrowMatch aa:5 .
I would like to provide a user interface where they do not need to 
concern themselves with concepts and collections.
>
>> In fact, as I have typed up this example I wonder if the A&A 
>> vocabulary snippet I have given is in fact valid in the new skos 
>> reference as is declares a collection to be a narrower term and this 
>> goes against the domain and range declarations for the BT/NT 
>> relationships.
>
> Yes, mapping a collection and a concept is not valid - but in practise 
> (as you have shown) it would be very useful. We could either broaden 
> the  domain and range of the mapping vocabulary or add a second 
> mapping vocabulary. In both cases you MUST declare some rules:
>
> <A> a skos:Concept .
> <B> a skos:Concept .
> <C> a skos:Concept .
> <X> a skos:Collection .
>
> <A> skos:narrower <X> .
>  <X> skos:member <B> .
>
> <X> skos:exactMatch <C> .
>
> entails
>
> <C> skos:narrowMatch <B>
 From the point of view of providing interfaces to users who do not want 
to concern themselves with what is a collection and what is a concept, 
these rules will be essential. This is in fact something I am in the 
midst of developing, a mapping editor for skos vocabularies.
>
>
> This could get a bit more complicated (for instance transitive member 
> relations) but makes sense.
I have not even begun to consider how transitivity affects this.
>
> Thanks for pointing to this issue.
>
> Greetings
> Jakob
>
Cheers,

Alasdair
[4] http://www.w3.org/TR/2008/WD-skos-reference-20080125/