[sc34wg3] Analysis of TMRM Use Cases

Steve Pepper sc34wg3@isotopicmaps.org
Mon, 12 Apr 2004 09:50:09 +0200

* Robert Barta:

| Still - having chewed again through the TMRM - I would think there is
| a strong need for - what I would rather call - "generic TM model". In
| that model we would not have "basenames" and "occurrences" but only
| associations (with a reification concept). And I mean ONLY
| associations. Everything else could be derived as a second-level
| concept.

I certainly see the attraction of having a "foundational" model
that has associations but not basenames or occurrences... At least
I see how that could be intellectually satisfying.

But I'm not sure I see what use we would have for it. And without
understanding what its purpose is, there is no way we can answer
important questions like:

* What happens to identifiers in such a model?

* Will such a model require us to be able to show how the same 
  information can be represented using associations instead of 
  base names and occurrences? (If so, are we sure that we will
  not open a can of worms in doing so?)

* To what extent are templating constructs required as part of
  the model?

* How far do we need to go in terms of defining the fundamental
  rules that apply to the model, such as (in simplified terms)
  "can a topic be both a topic type and an association role

Without answers to questions like these, we don't know enough
about the kind of model we need and so we can neither evaluate
current proposals or create new ones.

| TMDM (or whatever its name is now) would then be a particular
| "instantiation" in this generic model, exactly as Steve N., Jan,
| et.al.  have envisioned (thx to Jan for explaining this to me
| a while back).

Again, there is a certain intellectual satisfaction in this,
but it begs further important questions:

* What other "instantiations" already exist or might exist? 

* Do we want to call those "instantiations" Topic Maps?

* If so, to what extent does it serve or damage the interests
  of Topic Maps users for there to be multiple models, all of
  which can legitimately be called Topic Maps?

* To what extent should multiple "instantiations" of the
  generic model be interoperable?

This brings us back once more to requirements and use cases.

| I think the fact that they were trying to achieve something with
| __only__ a data model should not mislead us to believe that the idea
| itself is not worth pursuing.

I have never said that the idea is not worth pursuing. I'm not
sure anyone has (except possibly in a moment of extreme frustration).
It's a question of *how* we pursue the RM, and whether we let that
pursuit delay other parts of the standard.

We have to agree on "industry requirements" before we can proceed.
The use cases were intended to help in that process. Lars Marius
and I did our best to extract a real industry requirement from those
use cases and then demonstrated that that requirement could be
satisfied using the TMDM and TMQL. SRN and Patrick have since
claimed that we missed the point and have made another effort to
get that point across. I am still trying to get my head around
their latest contribution.

So, yes, I'm all for an intellectually satisfying generic model,
provided we first agree on its exact purpose in terms that make
it possible to standardize something that people actually have a
use for.

But this goes way beyond a mere restatement of 13250, which is
what we are supposed to be doing at the moment, and it is very
definitely *not* as urgent as TMQL and TMCL.


Steve Pepper <pepper@ontopia.net>
Chief Strategy Officer, Ontopia
Convenor, ISO/IEC JTC 1/SC 34/WG 3
Editor, XTM (XML Topic Maps 1.0)