RE : [SKOS] RE : Skos mapping issues

Hi Javier,

> > >
> > > Respect to the compositions of mappings through "and", "or" and "not"
> > > relationships I think that to be able to create complex compositions as
> > > (A and B and (C or (D and E))), it would be needed a specialization of skos
> > > concept (called for example conceptCollection) to group all the composed
> > > concepts and the type of composition.
> > >
> > > I see that there are some similarities in the "and" relationship respect to
> the
> > > pre-coordination of labels in a thesaurus, and also
> > > respect to the composition in USE relationship to refer from a complex label
> to
> > > two simpler ones. However, I think they are
> > > some semantic differences between the "and" and the coordination making them
> not
> > > completely interchangeable.
> >
> >
> > This was the point in [3] to treat this "and" problem in the context of a
> different coordination problem which is on the SWD agenda [4]
> > Your point about "and" and pre-coordination is valid. There are case of
> complex mappings with conjunctions that could well correspond to
> post-coordination cases, and [4] is too narrow for this.
> > So we should re-introduce post-coordination in the loop by means of some
> specific "and". Something which semantics should be roughly
> > if x match (y andpostcoord z) then (if doc skos:subject x then doc
> skos:subject y and doc skos:subject z )
> >
>
> I agree with this. However, I think that pre and post-coordination are focused
> in the labels more than in the concepts (labels of two or more concepts are
> composed to construct a multi word label that represents a new concept. The use
> of "and" is completely focused in concepts (two composed concepts by an "and"
> have an meaning equivalent to other one). It does not mater the labels of each
> concept.
> I see pre-coordination like adding a property to the concept, instead of
> generating a new combined meaning (from two different concepts). So, I agree
> with treating in a different way.

For me we can interpret pre-coordination at the conceptual level in the context of SKOS. The literature will talk about strings and terms (http://www.willpowerinfo.co.uk/glossary.htm#pre-coord) but don't forget that in the normal thesaurus word as indexing is done by means of preferred terms you will have less references to "concept".
Furthermore, when you look at pre-coordination cases (see http://www.w3.org/TR/skos-ucr/#R-ConceptCoordination), it really looks like we build new concepts from existing ones, changing their respective meaning.

The common point then would be the creation of some new subject/concept. Post-coordination would do it in an implicit way (just resulting from co-occurrence in skos:subject statement for a same document) while pre-coordination would do it explicitly, according to rules given in a vocabulary.

>
> Respects to the other types of composition "or" and "not". They are commented in
> the different thesaurus standards but I am not sure if they are really used in
> the "real word" to define mappings. Especially complex to use I find the "not"
> given that it only has sense in combination with "and" or "or". Do you know of
> a real mapping in which this types of compositions are used?.

Not. But such links could be generated to check an existing mapping, or to prevent misuses (e.g. for indexing) of aligned vocabularies

Cheers,

Antoine