[topicmapmail] Are Facets Really Simple After All?

[Miles Thompson]

Murray Wrote:

>> ..the idea  of being able to express simple triples=20
>> about a Topic without invoking  the whole Topic machinery
>> is what I have heard people yearn for since=20
>> we did XTM (and during its development).

Kal Ahmed wrote:

> The reason facets didn't make it into XTM was that it was felt that if
> this resource is something you care about enough to want to attribute
> property/value pairs to it, then you should create a topic that=20
> represents that resource and use occurrences. In other words,
> ISO 13250:2000 facets are a short cut for reification and using
occurrences.

So. My question is this..

Are there any semantic characteristics of facets (represented in some
property-value form) that could not *conceivably* be represented by some
construct as 'occurences' (that is, either of the subject represented by
the topic or of the topic itself ) ?

Seems to me, that if the answer to the above question is 'none, really',
then its reasonable to consider facets as 'occurances light' that is,
'short cuts'.

Now. Don't get me wrong here, I think that short cuts and
simplifications are important. [ I simply don't buy the argument that
you can construct a perfect 'model' with no regards for implementation
issues - in my opinion this is one of the things that went 'wrong' with
the VRML standard, and what caused it to be so ungainly and have such
slow uptake. ]

So... if the suggestion to include facets back into XTM can be thought
of as about making certain types of things 'easier' to represent. Then
we could potentially work backwards, and ask, what are the things that
occurances do, that we consider to be ungainly or too heavy for
representation of things like 'topic creation time' or dublin meta data
etc.

That is, could one work backwards and define the things that we would
want facets *not* to do (versus Occurances) ?=20

Could we even define that a facet is a type of occurance, but with
certain assumptions made vis-=E0-vis how datatypes (XSD), topic-type
hierachies etc operate?

Just an idea. I might be waaay off base ;-)

miles thompson