[topicmapmail] Are Facets Really Simple After All?

[Carlo Moneti]

On 2003.11.30 11:25 Thomas B. Passin wrote:

> If this is a reasonable way to look at facets, then I do not see why 
> using facets would be different in any essential way from classifying 
> using a single hierarchy.  A given topic could be related to one of the 
> faceted terms, say "location", by an association called, perhaps, 
> "hasFacet".  You would find out which particular facet tree that 
> "location" is in by walking up to the root of its tree to arrive at 
> "Geography", whose type would be "Facet".  Of course, a real 
> implementation would use some kind of shortcut to avoid actually walking 
> the tree each time.
> 
> Is there something I am missing here, or is it really this simple?

I have come to the same conclusion as Thomas. Just last night I resolved 
the following topic and association types:

topic type to define a facet (#facet-root)
topic type to define a facet category (#facet-category)
association type for parent/child relation of facet-categories 
(#facet-parent-child)
association type for topic as member of a facet-category (#facet-member)

This goes a long way in addressing my concern (perhaps needless) about 
polluting topic info with facet info, which seems to me like application 
infrastructure detail rather than true topic info. True topics won't be 
polluted in their occurrence data (as Murray also worried); and facet  
hierarchies, being differentiated from others, can be processed distinctly 
(turned on or off, as Murray pointed out). Also, many facet hierarchies may 
be generic enough to have a double use as non facet-related hierarchies.

This approach is convenient in that it addressess easily and intuitively (I 
think) the mapping of facet info from XTM to a relational database that 
some application will query to generate a faceted navigation experience. 
Now, perhaps this isn't ambitious enough. Perhaps there is in theory a way 
to inform a topic map and topic map engine of an equivalent of the 
aforementioned application logic and db queries, so that the topic map 
engine can generate a faceted navigation experience. This, however, is 
beyond my knowledge. Is anyone working on this, or theorizing such 
potential?

Cheers,
Carlo Moneti