[sc34wg3] a TM Application Definition example

Lars Marius Garshol sc34wg3@isotopicmaps.org
25 Apr 2003 12:45:15 +0200

* Steven R. Newcomb
| A Topic Map Application Definition is analogous to a Document Type
| Definition.  Both can serve as a basis for interchanging information
| between people who wish to interchange that kind of information.

That seems clear, but there is an enormous difference between them in
that a TMAD is a prose work whereas a DTD is used by machines and not
only humans. The conformance of a given DTD to the XML recommendation
can be judged by a machine, whereas the conformance of a TMAD must be
judged by a human.

| Similarly, the TMM serves as a foundation for a paradigm in which a
| single processing discipline -- variously implemented in various
| technologies -- allows any topic map, expressed in any syntax,
| representing an unbounded number of semantics, to be interchanged in
| conformance with that discipline.  

I don't see how that can happen. There is no syntax for interchanging
RM instances nor can there be any means for doing TMA evaluation
automatically unless a TMA implementation is custom-built for that
TMA. If one is, I don't see what help the RM gives the implementor of
that TMA.

| The author of a topic map can reasonably expect everyone in the
| world to get exactly the same results -- the same network of
| connected subjects -- from any conforming implementation.

How can that be when the formalism in N0393 only defines how to
compare "lists when treated as sets" and leaves everything else open?
If the author wrote a specification document (which is what a TMAD is)
that author could of course expect to get the results you describe if
the author did his job well, but that's no different from the
situation we would be in if N0393 did not exist at all.
| The answers to your questions...
| * What is a TMA good for?
| * What could someone use it for?
| * How could someone use it?
| * How would they be better off than they were before the TMA was
|   created?
| ... are the same for any particular TMA definition as they would be
| for any particular DTD. 

OK. I accept that that is the intention, but I don't think N0393 as it
stands, or is likely to stand in the next year or two, can achieve

| The power to create and interchange TMAs, and the power to create
| and interchange topic maps that are based on them, has at least as
| much value as the power to create and interchange DTDs, and the
| power to create and interchange SGML/XML documents that are based on
| them.  If you accept that this kind of power has value for
| interchangeable documents (SGML/XML), and if you accept that it's
| desirable to interchange networks of subjects (Topic Maps), then I
| think you must accept that the power to create and interchange TMAs
| also has value.  It is precisely because we cannot predict the full
| range of uses to which this kind of power will be put that we find
| SGML/XML -- and the TMM, in the case of topic maps -- so important.

I accept the logic of what you say, but you are not likely to be in a
position where you are ready to actually do this for a considerable
amount of time. Also, I personally do not find the model embodied in
N0393 at all attractive, so while I do think it is valuable to
exchange information I would much rather use XML or XTM to do it.

| The business opportunities that TMM-based technologies can afford
| will be far broader than the business opportunities for today's
| TAO-oriented technologies.

Personally, I don't think that is true, and in any case what is
described in N0393 is not yet a technology. It needs much more work
before it will be ready.
| Under the TAO idea, the Topic Maps paradigm only knows how to
| integrate information about subjects only in accordance with certain
| types of relationships:
| (1) the type of relationship that exists between a topic and one of
|     its subject indicators, and
| (2) the type of relationship that exists between a topic and its name
|     (if the name-based merging rule is enabled).

There's also associations, of course, which can represent any kind of
relationship at all.

In any case, I think what you write here makes it clear that you too
consider N0393 to be something different from what is currently in ISO

What you wrote higher up seems to say the same thing:

| [...] we already have a topic map standard that is very well adapted
| to being used in certain ways for certain things, namely, indexes,
| thesauri, glossaries, and the like.  In that limited world, everyone
| agrees that Topic Maps are marvelous.

I have to say I agree with that. N0393 is quite far removed from ISO
13250, and in my opinion (and, for the time being, ISO's) ISO 13250
*is* topic maps.
| Making the modules self-describing is also key.  The TMM is designed
| to allow TMAs to be self-describing, by allowing them to "build-in"
| their self-description facilities into every topic map they govern.
| (Which is exactly where their self-descriptions can do the most
| good.)

Well, this makes it clear what your goal is, but it also makes it
clear that you are still very far away from it. N0393 is a set of
guidelines for writing standards documents, not a technology that
enables anything. It does have the potential to become a technology,
but not in the immediate future.

Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >