Aside - Re: Question: DAML cardinality restrictions

On Fri, 30 Mar 2001, David Allsopp wrote:

>
> Dear all,
>
> I hope you'll forgive a (probably very naive) question: In the DAML+OIL
> walkthrough, we have the following example of a cardinality restriction
> (plus another minCardinality restriction).
>
>  <rdfs:subClassOf>
>     <daml:Restriction daml:cardinality="1">
>       <daml:onProperty rdf:resource="#hasFather"/>
>     </daml:Restriction>
>   </rdfs:subClassOf>
>   <rdfs:subClassOf>
>      <daml:Restriction>
>        <daml:onProperty rdf:resource="#shoesize"/>
>        <daml:minCardinality>1</daml:minCardinality>
>      </daml:Restriction>
>   </rdfs:subClassOf>
>
> "This requires that any person must have exactly 1 father and at least
> one shoe size. Again, this is done by first using a Restriction to
> define an anonymous class (in this case the class of all things that
> have exactly one father), and then demanding that Person is a subClassOf
> this anonymous
> class (i.e., demanding that every Person satisfies this Restriction)."

I can't help feeling a little worried by these examples. Yes, I know
they're "only" examples. But the model of the world they present is
broken - will DAML be good for describing the real world or just
mathematical arenas and EDI? Is it even wise to try the former - or
should the examples be rewritten to be less contentious?

jan "Human beings without feet are people too" grant

PS. According to Tuco, Blondie doesn't satisfy the first constraint
either :-)

-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287163 Fax +44 (0)117 9287112 RFC822 jan.grant@bris.ac.uk
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