Re: Relationships involving collections

Leonard Will wrote:

> You have shown "Gamma rays" as "Collection", but I hope that nobody
> would interpret it as that, in SKOS or elsewhere. It looks like an
> ordinary concept, and doesn't become a "collection" just because it has
> some narrower terms. As I understand it, "collection" is the SKOS term
> for what the thesaurus standard BS8723-1 calls an "array": a group of
> sibling terms. An array may be preceded by a node label showing a
> "characteristic of division", e.g. (... by wavelength) in the above
> example. Node labels are just interpolated explanatory labels; they do
> not represent concepts and they do not have relationships.

I don't see the problem: Of course you can create an array named "gamma 
rays" it makes a lot sense. Arrays and skos:collections do not imply any 
semantics for retrieval - they are just groups because it's useful for 
browsing, showing, printing... the hierarchy. You can group concepts by 
anything you want.

> You can't really make mappings between an array and a concept. If you
> want to map the whole group, you should probably be mapping their parent
> term. In this case the concept "gamma rays" occurs in both thesauri, and
> as its definition is presumably the same in both there should be no
> problem in making a direct mapping.

That's right. The mapping takes place between concepts so you map to the 
parent node and members of a collection. BUT in practise you just want 
to see or set ONE mapping relation to a collection instead of MANY to 
its parent and members. It's more one the level of user interfaces.

I have drawn a picture of Alasdair's example with GraphViz - maybe that 
helps:

http://esw.w3.org/topic/SkosDev/ClassificationPubGuide?action=AttachFile&do=view&target=skos-exactMatch-Concept-Collection.png

Greetings,
Jakob

--- GraphViz source ---
digraph G {
   nodesep=1.0 // increases the separation between nodes
   A [label="Sources of Wavelength"]
   B [style=dashed,label="Gamma Rays"];
   A -> B ;
   B -> C ;
   B -> D ;
   X [label="Gamma Rays"]
   X -> B [style=dashed, dir=both] ;
   {rank=same; B X}
   X -> C [style=dashed, label="narrowMatch"] ;
   X -> D [style=dashed, label="narrowMatch"] ;
   C [label="Gamma Ray bursts"]
   D [label="Gamma Ray theory"]
}


-- 
Jakob Voß <jakob.voss@gbv.de>, skype: nichtich
Verbundzentrale des GBV (VZG) / Common Library Network
Platz der Goettinger Sieben 1, 37073 Göttingen, Germany
+49 (0)551 39-10242, http://www.gbv.de