[tmcl-wg] Consistency of TMCL Schemas ?

[Lars Marius Garshol]

* Lars Marius Garshol
|
| I'm having a hard time working out what it is you are trying to say,
| or, to put it a different way, why you posted about this. What is it
| you are trying to tell us? Don't bother to create TMCL when we
| already have OWL?

* Bernard Vatant
| 
| The way you put it is an extreme conclusion to which I'm not yet
| arrived, but don't push me too hard.

The only thing I'm really pushing for here is clarity.

| For now, I meant simply that OWL can express a lot of things TMCL is
| intended to do, and I am not and will certainly not be the only one
| to explore that path, and use it that way.

I agree completely with that. There is an overlap and we need to
figure out what to do about it. I think it's also clear that simply
saying "we'll adopt OWL as-is and turn TMCL into a description of how
to use OWL in topic maps" won't be enough.

| What I wonder is what will happen when TMCL is here. 

I think we all wonder about that. :)

| People will certainly want to find at least features found in OWL,
| and that's why I was pointing at internal consistency of TM schemas,
| among other needed features.

I think internal consistency might be a reasonable requirement for
TMCL, though I'll leave that for the editors to judge.
 
| And another concern is that it seems to me that TMCL is aiming at a
| high level of expressivity requirements, maybe against usability.
| And yes, I have a concern about the pace of TMCL development, and
| the high level of requiremnts will not help. I know what the reasons
| are, but I am really afraid that if TMCL comes too late on the scene
| and is too complex, it will have hard time to be adopted.

I think your concerns are entirely reasonable, and in fact I share
them. I think the only thing we can do is make sure TMCL isn't too
complex, and that we get it out as soon as we can. There's not really
all that much else to do or say, I think, at least not right now.

| Have you any idea of when it will happen?

Ask the editors. (We already have a strawman, though. Comments on that
would be helpful.)

| 2. OWL is *not* another RDFS vocabulary. It's an ontology language
| that happens to use the RDF syntax and data model. The main interest
| of it is the expressivity of its abstract model, not the RDF
| representation (which is maybe more of a drawback than anything
| else.)

That's an interesting take on it. OWL certainly is expressed as an RDF
vocabulary, but I agree that that doesn't mean you *must* use RDF to
be able to use it. As I argued in my paper large parts of OWL can be
used in topic maps (with XTM syntax and all) right now. (Also, as I
argued, some parts of OWL are unnecessary in topic maps.)
 
| 3. OWL is candidate tool for interoperability of a large variety of
| Knowledge Organization Systems. People work currently on migration
| in OWL of a huge legacy of taxonomies, thesaurus as well as formal
| ontologies ...  with this global objective of semantic
| interoperability which, remind you, is the original aim of topic
| maps. 

All well and good.

| So, keeping the topic maps family of standards on its own track
| without taking this context into account seems to me a deep error.

I think the main mistake is to assume that OWL is not being taken into
account. I also think that TMCL and OWL may be more different than you
think. 

I think the following might be the best solution:

 - create a TMCL that handles constraints on topic maps, kind of like
   RDFS and constraint parts of OWL, and

 - reuse the ontology parts of OWL that make sense in topic maps as a
   separate specification.

The reuse might take the form of expressing OWL in topic maps pretty
much the way an OWL schema would look if converted to topic maps using
the Ontopia RDF->TM mapping vocabulary, or it might be reengineered
somewhat (new URIs, for example), but include a simple and clear
description of how to map RDF OWL to TM OWL.

My mind isn't really made up on any of this.
 
* Bernard Vatant
|
| So far, I've been quite happy with OWL expressivity for constraining
| topic maps.

* Lars Marius Garshol
|
| What do you mean by "topic maps" in this case? RDF?
 
* Bernard Vatant
|
| I suppose I have to take this remark as being deliberately
| provocative, and I won't answer to it.

No, I mean it quite literally. It's not really possible to understand
how you use OWL without knowing what kind of data model you are using
it to constrain. If you use RDF then it's clear how you are doing it.
If you use topic maps then it's not at all clear how you do it, and
I'd be interested to hear it. 

And if you use something else that's similar to RDF and similar to
topic maps, but not really 100% like either, well, then that would be
useful to know, too, although then the reply to how you use OWL would
probably be less useful, since nobody else would be in exactly the
same position.

| There is one thing I will agree with you anyway. I wonder why I
| posted here, and will refrain to do it any more.

Why not? Because I asked you whether you were using topic maps or RDF?
What was it I said that was so bad? (Reply off-list if you prefer.)

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