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Re: LANG: Nested Class definitions and the RDF striped syntax

From: Jonathan Borden <jonathan@openhealth.org>
Date: Sat, 23 Mar 2002 01:19:49 -0500
Message-ID: <004c01c1d232$bd98f3c0$0301a8c0@ne.client2.attbi.com>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <Frank.van.Harmelen@cs.vu.nl>, <www-webont-wg@w3.org>
Peter,

>
> Actually, I don't believe that OWL-Lite will solve the round-tripping
> problem.  I believe that the round-tripping problem is inherent in RDF,
> unless the encoding into RDF looks very different than DAML+OIL.

Fine. As I have said, these sorts of round tripping problems are often
difficult.

My issues were _specifically_ related to the statement that nested class
definitions were the cause of the problem, which is why OWL Lite does not
allow them. If OWL-Lite does not solve this problem, i.e. if the problem you
are referring to is not solved by restricting the language to top level
definitions (in the XML source) then I don't see the argument for this
restriction.

>
> > 2) I agree, and suggest that OWL with nested class definitions can be
> > transformed into 'top level'
>
> I believe that this is not an adequate solution.

Ok what is?

>
> I do not believe that this is an adequate solution, for the reasons stated
> in
>
> Sean Bechhofer, Carole Goble, Ian Horrocks.
> DAML+OIL is not enough.
> SWWS-1, Semantic Web working symposium, Stanford (CA),
> July 29th-August 1st, 2001.
> http://potato.cs.man.ac.uk/papers/not-enough.pdf

I've read that, but perhaps it is not a perfect description of the problem,
particular for an "outside" reader.

The example _ends with_ a DAML+OIL description, which is stated to be the
problem, but it is not clear to me why my 'solution' to this problem doesn't
work ... and so far no one has given me a specific example _in DAML+OIL_ of
why it won't work.

>
> Actually, RDF collections do preserve order, even when one would like them
> not to.  The problem with RDF collections is thus not related to ordering
> but to well-definedness and closure.

Agreed.

>
> Well the round-tripping problems are addressed in the paper referred to
> above, which has an example.

The example isn't in DAML+OIL. It is in another language. Let's be specific
about this: the problem with nested class definitions very well may exist
for _another language_. The question exists whether this (same) problem
exists for DAML+OIL. You should know that I am not one to sing the praises
of RDF when there is something wrong (e.g. I do agree with
"daml:collection", but on the other hand, this _specific example_ is perhaps
one that RDF has gotten right. If not, please explain with RDF examples so I
can see.

>
> The White-van-man in the paper referred to above does, I believe,
> illustrate the problem.
>

Again the "white-van-man" problem in the paper is largely not in
RDF/DAML+OIL. It is mostly in _another language_

but how about this (in the non-XML syntax I have just described)

class white-van-man (
       subClassOf Man,
       property drives(string "white van")
      )

now "covered White-van-man by Aggressive-driver" I have trouble
interpreting, so perhaps you can help.

The point being that the crux of the argument is in this last statement
which as far as I know has no normative DAML+OIL equivalence, hence the
problem might just be how this statement is being interpreted?

Jonathan
Received on Friday, 22 March 2002 13:14:05 GMT

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