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n-ary datatypes

From: Turner, David <davidt@hp.com>
Date: Tue, 6 Feb 2007 14:19:16 -0000
Message-ID: <86FE9B2B91ADD04095335314BE6906E8D6D471@sdcexc04.emea.cpqcorp.net>
To: <public-owl-dev@w3.org>

Hi,

I've recently started working with Jeremy Carroll at HP, initially
focussing on OWL 1.1. At the moment I'm reading through the specs, and I
have some questions about n-ary datatypes as implemented in OWL.
Fundamentally, I am having trouble seeing how n can be anything other
than 1.

>From section 5 of [1]:

> This is in order to support class definitions such as "objects whose 
> width is greater than their height", where the values of width and 
> height are specified using two data properties. In such definitions, 
> the arity of the given data range must be equal to the number of the 
> given data properties."

which seems to be the only place in the document that mentions the
possibility of non-1 arities. How, exactly, would one go about defining
the class of objects whose width is greater than their height?
Presumably the  intention is to have a datatype of arity two, whose
extension is the graph of the relation '>', but I cannot find the
appropriate syntax to define this. I would like to understand how to

(a) define a datatype, arity 2, being the product of the width and
height datatypes, then
(b) restrict this datatype down to those pairs <width, height> where
width > height.

It is not obvious how to do either (a) or (b) within OWL. The collection
of XML Schema facets seems only to be relevant to unary datatypes, so is
of no help here.

Cheers,

Dave Turner


(Incidentally, [1] makes the false claim that its canonical version
lives at http://owl1-1.cs.manchester.ac.uk/syntax.html - this link is
broken).

[1] http://owl1_1.cs.manchester.ac.uk/owl_specification.html
Received on Tuesday, 6 February 2007 18:46:35 GMT

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