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RE: Reified relations in OWL

From: Paul Oude Luttighuis <Paul.OudeLuttighuis@novay.nl>
Date: Fri, 26 Feb 2010 17:16:04 +0100
Message-ID: <FD63C26145CC0547B67E6BDD29A65A1701C2305C@exchangebe1.corporate.telin.nl>
To: "Uli Sattler" <sattler@cs.man.ac.uk>
Cc: <public-owl-dev@w3.org>
Dear Uli,
Thanks for your swift reply.
I'm hesitant about extensively elaborating on our modelling approach in this forum. It's not the place. If you like, we can do that via direct e-mail.
But, to answer your last question: basically, I would like relations to be able to participate in relations themselves. In fact, in the modelling approach we study, this is the rule, not the exception. Relations are hence first-class citizens, or even, the only citizens ... Each concept is represented by a relation that connects the concepts it is existence-dependent upon. So, it requires relations to have their own instances. This is what I know as "reified relations".
We are looking for modelling languages that might nicely express such reified-relations-only models. OWL is only one of them. Our first concern is not reasoning, but plain representation, preferably with a nice graphical syntax.
Does this help?


From: Uli Sattler [mailto:sattler@cs.man.ac.uk] 
Sent: vrijdag 26 februari 2010 15:24
To: Paul Oude Luttighuis
Cc: public-owl-dev@w3.org
Subject: Re: Reified relations in OWL

On 25 Feb 2010, at 21:53, Paul Oude Luttighuis wrote:

	Dear OWL mailing list,
	In a current project, we take an approach to semantic modelling based on reified relations only. In that context, I am looking for ways of using reified relations in OWL. I am aware of the ways of mimicking reified relations proposed in http://www.w3.org/TR/swbp-n-aryRelations/, but these yield awkward models. Also, such mimicking takes away the graphical visualisations we need, as these tend (as in Protégé) to visualise the subtyping hierarchy only, not the relations (properties). In our case, subtyping is refrained from/not interesting.

sorry for skipping over your initial question: why would you refrain from 'subtyping'?! The fact that you use the term 'subtyping' seems to indicate a misunderstanding of the OWL semantics...so perhaps this should be clarified first: e.g., in OWL, if you define the class "Waterbirds" as those Birds who live close to water, and Ducks as those Birds who say quack and live close to water, then the subclass relationship between Ducks and Waterbirds will be entailed, and thus inferred by the reasoner...as a consequence, every instance of Duck will also be an instance of Bird, automatically, simply due to the OWL semantics...

Now, perhaps you explain your 'reified relation' scenario a bit more: I assume you want to model n-ary relations/tuples, for n>2? Do you have an example?

Cheers, Uli 

	Am I overlooking something. Can anybody point me to more natural ways of modelling and graphically representing reified relations with OWL?
	I'd be grateful for your suggestions.
	Best regards!



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Received on Friday, 26 February 2010 16:17:26 UTC

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