[Requirement][SKOS-Core] Arrays of concepts

Hi all,

We made a good start on this issue earlier in the year, here is a write up
of the specific requirement ...

[see also <http://esw.w3.org/topic/SkosDev/SkosCore/CollectionsAndArrays>]

Many thesauri group small sets of concepts under what's called a 'node
label' or 'guide term', for example this from the AAT ... 

chairs 
   <chairs by form> 
      armchairs 
      ax chairs 
      backstools 
      Barcelona chairs 
      barrel chairs 
      ...  

... or this from the English Heritage thesaurus of historic aircraft ... 

AIRCRAFT 
     AIRCRAFT <BY FUNCTION> 
          TEST AIRCRAFT 
          FIGHTER 
          BOMBER 
          TRAINER 
          TRANSPORTER 
          RECONNAISSANCE 
          TARGET 
          ARMY COOPERATION 
          TUG 

This type of collection of concepts is commonly called an 'array', where the
array label identifies some 'characteristic of division' for the contents of
that array. 

The consensus seems to be that the node label (i.e. 'chairs by form' or
'aircraft by function') should not be modelled as a label for a concept in
its own right, but rather as a label for a collection of concepts. 

The matter is complicated further because in some arrays, the ordering of
concepts is meaningful. However, in other arrays the ordering of concepts is
not meaningful. The RDF description of an 'array' must therefore provide a
way to distinguish between these two cases, primarily so that applications
handling the data can know whether they should preserve the original
ordering, or whether they are free to reorder the contents of an array by
some criterion, for example alphabetically. 

SKOS-Core requires some framework for supporting arrays of concepts as
described here.



---
Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
Chilton
Didcot
Oxfordshire OX11 0QX
United Kingdom
Email:        a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440

Received on Monday, 9 August 2004 14:27:32 UTC