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RE: [OEP] public comment

From: Peter Mika <pmika@cs.vu.nl>
Date: Fri, 4 Jun 2004 12:15:25 +0200
To: "'Natasha Noy'" <noy@SMI.Stanford.EDU>
Cc: <public-swbp-wg@w3.org>
Message-ID: <001001c44a1c$dac09390$fb1e2582@fspc055>

Dear Natasha,
(cc: SWBP-WG)

> Or OWL Full for that matter. However, this is an interesting point,
> perhaps adding this possibility as one of the bullet points for
> approaches 2 and 3 would make sense. I'll do that for the next version
> and see what other say.

It can be expressed in SWRL (Patel-Schneider and Horrocks, WWW2004).
But if you don't want to commit to any particular representation (since
that game is not over yet...), then you might choose to stay with a
plain old FOL formula :) BTW, it seems like Approach 3 could also use
some rule to keep the two hierarchies consistent. (However, this rule
cannot be defined without committing to a particular parentSubject
property and then better left to the user...)
> You have a point there, and others have raised similar issues [1],
> I am not sure (1) is a feasible option though -- see my reply to Brian
> today. On (2) indeed translations between patterns would be helpful.
> Short of providing the translation tools themselves what type of
> information should we provide in the note to enable  tool developers
> write conversions?

Let me just brainstorm aloud and correct me later if my logic goes
astray somewhere.

We have five ontologies, which potentially means 4*5/2=10 mappings to
do... Alternatively, we could map all of them to a selected approach (to
the _least_ expressive one?) or to a foundational ontology that captures
concepts on a higher level than the individual ontologies themselves. 

Aldo and I have used the foundational approach in the past, but it
carries a lot of commitment, so now let's just look if it's possible to
find internal mappings. For the sake of argument, I'll try to map
Approach 2-5 to Approach 1. (Simply by looking at the number of boxes,
Approach 1 seems to be the least expressive, which holds the promise
that we can project the other ontologies onto this one.)

Note: I'll have to index the dc:subject property with the number of the
approach, since it is simply not possible that all approaches are
talking about the same dc:subject property... For one, they do range on
very different things.

Note also that I don't introduce any type restrictions; I guess this
document would not want to mandate the use of, for example, a certain
Subject concept as a top level class of all subjects.


Approach 2 -> 1:

(x, dc:subject_2, y) AND (y, rdf:type, z) -> (x, dc:subject_1, z)

Approach 3 -> 1:

(x, dc:subject_3, y) AND (y, rdfs:seeAlso, z) -> (x, dc:subject_1, z)

Approach 4 -> 1:

Seems to be the same as 2 -> 1, but again a different use of dc:subject
(one that ranges on Lions and not Subjects. (Without foundations, we
will never resolve this distinction, however.)

Approach 5 -> 1:

Same as Approach 1, except that dc:subject_5 is an annotation property,
which puts limitations on it when looked at it as OWL DL.

In summary: such mappings are possible, at least for translating the OWL
DL approaches to the simplest OWL Full version. The translation is not
expressible in OWL Full, however. Also, there is a need to distinguish
the five separate uses of dc:subject, which might actually be the
solution for the question of how a machine could tell the different
approaches apart.

The other direction of translation (not presented here) seems also
feasible, even if with some existential quantifications.



> Natasha
> [1]
Received on Friday, 4 June 2004 06:16:00 UTC

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