Re: Domain/Range: conjuntion or disjuntion??

From: tarod@softhome.net
Subject: Re: Domain/Range: conjuntion or disjuntion??
Date: Wed, 21 Nov 2001 15:42:39 GMT

> 
> Peter F. Patel-Schneider writes:
> 
[...]

> > >   What I wanted to explain is that a object CarsAndMotos must be instanceOf
> > > Car and instance of MotorCycle, so the 'trick' we use here works as we
> > > wish, but an instance of Vehicle should not be instance of Car neither
> > > MotorCycle, so the trick proposed here doesn't work.
> > 
> > But it doesn't work to capture the conjunction, which appears to be what
> > you are trying to achieve.  If you want the range to be the intersection of
> > Car and Motorcyle you don't get that from CarsAndMotos.
> > 
> > >       - Marc
> > 
> 
>   What I wanted to achive is represent that the Domain of the property is
> Car and MotorCycle, and you get that from CarsAndMotos, because
> CarsAndMotos is subclass of Car and subclass of MotorCycle, so, if the
> domain of the property is CarsAndMotos, the Subject of a sentence will be
> an instance of CarsAndMotos, so, it will be an instance of Car and an
> instance of MotorCycle too. That's the goal I was looking for. Did I miss
> anything?
> 
> > peter
> > 
> 
>   Thanks,
>          Marc

I think that you did miss something.  CarsAndMotos is not the intersection
of Cars and Motorcycles, just a subclass of that (inexpressible-in-RDF)
intersection, just as Vehicle is a superclass of the (inexpressible-in-RDF)
disjunction of Cars and Motorcyles.

Both tricks get part of what is needed; both tricks do not get exactly what
you might want.  Sometimes the trick is adequate; sometimes it is not.

peter