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

From: Jonathan Borden <jonathan@openhealth.org>
Date: Fri, 22 Mar 2002 23:31:23 -0500
Message-ID: <003601c1d223$9abdc1a0$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 F. Patel-Schneider wrote:

>
> This is not sufficient to prevent round-tripping problems.
>
> What would be sufficient would be to also show that there is an inverse
> transform from the ``top-level'' syntax to the ``nested'' syntax that
> results in a knowledge base close to the original.  Otherwise it is
> possible that a nested syntax knowledge base is transformed into a
> different-looking knowledge base, and that the differences in appearance
> are significant.

1) You are suggesting that OWL-Lite will solve the round tripping problem
2) I agree, and suggest that OWL with nested class definitions can be
transformed into 'top level'
3) I am not sure that any _requirement_ for the language states that one
must be able to roundtrip between the lexical (XML) syntax and RDF
4) XML document editors have difficulty 'roundtripping' between XML
documents and the internal DOM format (for example), these difficulties are
well known, well described, editors need to deal with it.
5) However, I am suggesting that tools which wish to roundtrip create
ontologies using the 'top level' idiom, in which case such tools and their
users will be happy.

[...]
>
> > Perhaps I am missing something? Of course the other option is to edit
your
> > ontologies as XML and parse as RDF when needed. This is how most XML
> > systems do things, e.g. even though XML is parsed into an internal
object
> > model e.g. the DOM, _editors_ don't edit the DOM, they edit the XML.
Indeed
> > if I were writing an ontology editor, I would edit your abstract syntax
> > directly and then generate XML/RDF from that. I will say more about this
> > later.
>
> What you are missing is that round-tripping has to end up with a knowledge
> base that has the same extra-logical connotations (whatever they may be)
as
> the original knowledge base.  These extra-logical connotations may include
> even such things as the order of definitions.
>

Is so-called 'round trippability' a requirement? goal?

I thought that by defining the model theory _on the set of RDF triples_ that
the so-called KBs would be in some way equivalent. Isn't that the whole
point of this exersize?

Regarding "order of definitions" this is an important point. This is why I
feel that preserving rdf:parseType="daml:collection" is important because
RDF as opposed to XML, does not normally preserve order. _daml:collection_
of course does. Hence when order is important the contents should be in a
daml:List.

Well, DAML+OIL already does that.

Look, you've made a proposal to significantly change DAML+OIL. My
understanding of the ground rules is that this would be acceptable, _if and
only if_ there is a significant benefit. Rather than you asking _me_ to
create some sort of proof that my point is applicable, instead I ask you for
a simple example, written in DAML+OIL (XML format) which illustrates the
problem. This example should be the approximately the simplest that
illustrates the problem. If I produce a counter-example, also written in
DAML+OIL, I would like you to explain to me why I am incorrect.

I am just trying to understand the issues. On the other hand I have already
spent at least a solid day this week on OWL and intend to spend more time
this weekend -- I am writing up a non-XML surface syntax which is similar to
the proposed OWL abstract syntax, yet is largely (perhaps completely)
compatible with DAML+OIL -- in any case please send me back a simple
concrete example which illustrates the problem, as that will be the best way
of convincing me that a real issue exists.

Jonathan


Jonathan
Received on Friday, 22 March 2002 11:25:46 GMT

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