[sc34wg3] Alignment of N0396 with N0393

Jan Algermissen sc34wg3@isotopicmaps.org
Tue, 29 Apr 2003 08:58:23 +0200

Lars Marius Garshol wrote:
> * Jan Algermissen
> |
> | The alignment of N0396 with N0393 is now online at
> | http://www.isotopicmaps.org/tmmm/TMSM-1.3/TMSM-1.3.html
> My first question about this document is how it is intended to be
> used. Is it just a rough draft showing a first attempt at a SAM-RM
> mapping that is intended to live together with SAM and RM, or is it
> intended as a replacement for N0396? Clarification on this would be
> welcome.

Well, it shows the approach to be taken for expressing the ontological
commitments of N0396 in terms of N0393.
> On reviewing the document a number of shortcomings become apparent.
> Some are simple bugs (like the definition of the 'text' data type),
> others are omissions, and a last category is more subtle. I think it's
> clear that the simple bugs can easily be fixed, and it would seem that
> the omissions can also be handled (though I'm not too sure). The last
> category I am not sure the RM can handle at all.

Certainly the document is not 'ready' but it's sole purpose is clarification.

> The omissions are obvious, and some are even stated in the document.
> The TMA leaves out the PSIs for variant names, the
> unique-characteristic PSI, as well as variant names. These should be
> added once the author has time to do so.
> The subtle problem is that the merging rules are wrong. Subject
> identifiers and source locators share a namespace, 

Oh, what does that mean?

> but this is not
> modelled. Further, base names are here merged if they have the same
> string value, 

They are not. Why do you think so.

What do you mean by 'base name'? The name(-string) or the naming characteristic?

> even if their scopes, types, and parent topics are
> different. Finally, I can see no indication that duplicate topic
> characteristics are removed as they ought to be.

N0393 handles that completely (equal assertions are merged).

> What is much worse is that I am not convinced that the RM as it
> currently stands can overcome these problems. 

Well, it surely can but in our conversation we figured out already that the
prose of N0393 is not clear enough for a number of people to understand how. 

> So in order to
> conclusively prove that the SAM can be modelled in the RM this would
> have to be corrected.
> SAM associations are also modelled as RM assertions, despite the fact
> that these are structured differently, 

Why are N0396 associations structured differently from N0393 assertions?

> and there are some other warts.


> How serious these are is difficult to judge.
> Another subtle problem is that a number of things that are handled by
> the infoset formalism in the SAM is done by prose in the RM, 

Which ones?

> which in
> my opinion is not good, and it also seems to indicate that the RM as a
> formalism is less suited than the infoset is.

"seems to indicate..." ??

> This would also seem to be borne out by the fact that this document is
> much less understandable than the SAM is. 
> Back in 2001 when we were
> discussing suitable formalisms for modelling topic maps I proposed
> using EXPRESS, an existing and very suitable ISO standard, but was
> told that however suitable it might be the problem was that most
> people did not know it, so it would not communicate well. The RM
> suffers even more from this, of course.

The prose of N0393 may be unclear, but I don't see how the infoset
formalism is more clear that a property based model?
> The RM only adds value over and above the infoset if it simplifies the
> expression of the SAM. To me it seems obvious that rather than
> simplifying the SAM it considerably complicates the modelling of it.

So do you think that a 15+ pages document is less complicated than a
3 pages XML doocument (that can evetually even be processed by software)?


The draft alignment contains a suggestion for a slight modification of
the model in N0396 in order to reduce the complexity of that model. I'd
be curious what you think about this proposed change.


Thanks for your review.

> --
> Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
> GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >
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Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org