Re: n-ary datatypes

David,
Is R3 (coordinates) an example of n-ary datatypes?
Hans

----- Original Message -----
From: "Turner, David" <davidt@hp.com>
Date: Tuesday, February 6, 2007 3:19 pm
Subject: n-ary datatypes

> 
> 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 
> definingthe 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 
> collectionof 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 Wednesday, 7 February 2007 07:23:44 UTC