Re: Domain/Range: conjuntion or disjuntion??

Peter F. Patel-Schneider writes:

> 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

  Tricks almost never work as you hope, I agree with that. My point was,
you can be sure that an instance of CarsAndMotos is instanceOf Car and
instance of MotorCycle, but you can't not be sure that instance of Vehicle
is instance of Car or instance of MotorCycle.

  So, with CarsAndMotos I can simulate the conjuntion view of domains, but
with Vehicles I can't simulate the disjuntion view of domains (and ranges).
  For DAML projects, with CarsAndMotos you can perform inference without
any problem.

  Regards,
         Marc

Received on Wednesday, 21 November 2001 11:51:09 UTC