[tmcl-wg] Consistency of TMCL Schemas ?

[Lars Marius Garshol]

* Bernard Vatant
|
| Lars Marius, I just said I would not post here any more, but you
| made me change my mind. Thanks for that.

Thanks for not giving up entirely. It would have been very sad to see
you go.
 
* Lars Marius Garshol
|
| 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.
 
* Bernard Vatant
|
| Certainly it won't be enough. But we'll know what is lacking when we
| have tried it.

That's true. It might be an experiment worth trying, in order to give
people something they can use right now, and in order for the
community to learn from it.
 
* Lars Marius Garshol
|
| 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.
 
* Bernard Vatant
|
| Certainly, they will be built on different data model.

Sure, though I realized you'd caught on to that. :-)

What I meant was that TMCL may have more of a constraint focus and
less of an ontology focus than you expect. In fact, I think that if
people want TMCL to have ontology parts as well they should speak up
and try to get it into the requirements.
 
| What do you mean by "constraint parts" and "ontology parts" of OWL,
| exactly?

If you look at <URL: http://www.w3.org/TR/owl-features/ > I'd roughly
categorize these features as:

  CONSTRAINTS              ONTOLOGY                METADATA
  ===========================================================
  rdfs:domain              Rest of RDFS            Annotation
  rdfs:range               Equality                Versioning
  owl:FunctionalProperty   owl:inverseOf           Header
  owl:InverseFun...        owl:TransitiveProperty
  Restricted cardinality 

I know this isn't complete, but I need to get to bed soon. :)

Basically, not all of OWL is constraints. Some of it is just a kind of
semantic annotation, and that's the bit that I'd call the "ontology
part", except for the bit in "METADATA" above, which talks about the
ontology more than the domain (except for rdfs:label and rdfs:comment,
which talk about the domain, but are not machine-processable).

* Lars Marius Garshol
|
| 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.
 
* Bernard Vatant
|
| So you are open to the notion of TM OWL (or OWL-TM) as a specific
| OWL vocabulary. 

Yes. I'm not convinced we should do it, but I'm not convinced that we
shouldn't, either.

| I'm not sure if it should be grounded on a lower level RDF -> TM
| mapping, though.

I think it shouldn't, but you can convert OWL to TM that way and get
something that we could use. (The spec could then basically not talk
about how we got there.)
 
* Lars Marius Garshol
|
| 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.
 
* Bernard Vatant
|
| It's definitely topic maps constructs that are constrained this way,
| namely:
| 
| - Allowed classes of topics, and class-subclass relationships
| - Allowed association types and role types
| - Constraints linking association type, role type and class of role player
| (including cardinality)
| - Constraints on occurrence type for a topic class (including cardinality)

That does sound very much like topic map constructs, but how do you
say that something must be an occurrence type rather than an
association type? And how do you constrain association role types?
Surely OWL alone can't do that?
 
| Constraints on other TM features are not addressed yet, including
| scope.  Maybe they can't, and will need specific language. But there
| is already a lot you can do with the above, and it can be a good
| start for interoperability platform, since you can interpret this
| way features in a "native" OWL ontology (not intended for TM) and
| make your TM "commit" to them.

Agreed.
 
| BTW I've submitted a paper on this subject for XML Europe, and if
| it's accepted, we'll have a chance of discussing it in Amsterdam
| (around a beer).

That would be very interesting, and it does sound like something that
would be approved. I was about to propose that we do a joint paper on
this, but if you already have a solution to this that you'd like to
present you should probably just go ahead with that.
 
* Lars Marius Garshol
|
| 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.
 
* Bernard Vatant
|
| Agreed, and actually, there are a few bits of OWL that we will apply
| specifically to Mondeca ITM data model and that are irrelevant to
| TMDM, like for example representation of our structured "data
| items", which are neither XML Datatypes nor XTM occurrences,
| actually.

Right, that makes sense.
 
| Well, I honestly took the question as provocative. Sorry about that.

No problem. I can see how it could be read as provocative, even if it
wasn't meant that way.

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