RE: how to: ordered collection of a Concept

(Lots of threads are mixed here. Please read carefully just the parts marked **)

> > AAT has notations, these are the primary keys of concepts, e.g. "300019279" is "Iron Age".
> The AAT number that you refer to above is a concept identifier, not a
> notation. The ISO model provides for both of these, the distinction
> being that generally the identifier is an arbitrary number or symbol,
> permanently associated with a concept even though changes in scope and
> labels. A notation normally has some inherent significance

I think that identifiers quite match the definition of skos:notation given in the SKOS Primer and SKOS Reference (they don't say a notation should be sortable).
Anyway, I've added this issue (also raised by Marcia yesterday) to a list "AAT Questions" to be resolved soon.

> > Each skos:OrderedCollection (or iso:ThesaurusArray that is ordered) may impose its own list on its members.
> > In the case of the Getty thesauri, the list of members may vary in the poly-hierarchy, but the order between them will be always the
> > same. In other thesauri, it may be different.
> I don't know any examples, but in any well-structured thesaurus the list
> of narrower concepts under any concept should be the same wherever that
> parent concept occurs in a polyhierarchy.

Sure it is. But a subset of these children may appear under another Guide Term.

> > My question is how to order the children of a *concept*.
>       Iron Age
>                  Early Iron Age
>                  Middle Iron Age
>                  Late Iron Age
> 
> The latter three concepts are just a standard array, as shown in the ISO
> model, with the SuperOrdinateConcept "Iron Age" 

> The above array could have had a node label, as shown here, but this is
> optional in the ISO model:
> 
>       Iron Age
>            <Iron Age periods by time>
>                  Early Iron Age
>                  Middle Iron Age
>                  Late Iron Age
> 
> There does not seem to be any need to introduce something new such as
> the "iso:equivalentArray" you suggest.

*** So do you suggest to use an *anonymous* Array, having no labels?
I like this suggestion, because it emphasizes the inferior nature of this array:
it's not a level in the hierarchy (the Concept is that level).

My suggestion "iso:equivalentArray" would just link the concept to the inferior (parasitic) array, 
but won't emphasize the array's inferior nature. Your suggestion is better.

> > Unfortunately both SKOS and ISO are adamant that Concept is disjoint from Collection, Array and Group.
> True. Arrays and ConceptGroups each contain one or more Concepts. I
> assume that this makes them disjoint from Concepts.

When you put concepts under concepts, isn't that very similar to concepts under an array/group?

>  I can't comment on "Collections", as this is a SKOS idea that does not occur in the ISO model.

But it's important since Johan's implementation of ISO in OWL uses the SKOS collections (which is correct).
The SKOS collections are deficient since you can't put them under anything, but combined with ISO features this is resolved.

> > But neither has thought that Concept shares a lot of features with Collection, Array and Group:
> > they all have labels, they can hold children, those can be ordered.
> > This causes spurious differences in representation, that we should strive to eliminate as much as possible.

> How do you suggest that the representations could be made more similar,
> while preserving the distinctions between these disjoint elements.?

This is easy in RDF: keep properties agnostic as to domain and range, use the same properties in most situations, and use specific types to express the distinction.
SKOS has followed this pattern re Labels (skos:pref/altLabel have no domain/range, and skosxl:pref/altLabel have only range=skosxl:Label), so you can apply them to anything.
See next email in the mlist on Group/Array labels (with language and provenance)

> Concepts within a ConceptGroup can be ordered, because they can have a
> notation which can act as a sort key.

But SKOS doesn't specify such feature of skos:notation, and says ordering's done with an rdf:List inside a skos:OrderedCollection.
Also, in the ISO domain model, Groups don't have an "ordered" flag, unlike Array

> You probably don't need ConceptGroups to represent the Getty thesaurus

Good!

Received on Monday, 11 November 2013 17:07:42 UTC