[Sigia-l] Faceted approach applied to content

[Karl Fast]

> I'm under the impression that the the mutual exclusivity rule means
> that you should never construct a scheme where a value could exist
> under more than one facet/attribute.

There are cases where a term can exist under multiple hierarchies.
This is called polyhierarchy and it's reasonably common.

'Thesaurus Construction and Use' (Aitchison, Gilchrist, & Bawden)
list this example (among several):

Ear 
  NT Acoustic Nerve

Nerves
  NT Acoutistic Nerve

Acoustic Nerve
  BT Ear
     Nerves

The term 'acoustic nerve' can be correctly assigned to these two
hierarchies.

Pepending on your scheme these two hierarchies may be under separate
facets or they may not be. But either way, the mutually exclusivity
principle does not preclude polyhierarchy.


--karl