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RE: intersectionOf and subClassOf

From: Geoff Chappell <geoff@sover.net>
Date: Sun, 30 Mar 2003 13:36:23 -0500
To: "'Enrico Franconi'" <franconi@inf.unibz.it>, <www-rdf-logic@w3.org>
Message-ID: <002801c2f6eb$47210910$835ec6d1@GSCLAPTOP>



> -----Original Message-----
> From: www-rdf-logic-request@w3.org
[mailto:www-rdf-logic-request@w3.org]
> On Behalf Of Enrico Franconi
> Sent: Sunday, March 30, 2003 10:51 AM
> To: Geoff Chappell; www-rdf-logic@w3.org
> Subject: Re: intersectionOf and subClassOf
> 
> 
> On 30/03/2003 16:10, Geoff Chappell wrote:
> > If A is a subClassOf B and C, should an owl (full) reasoner infer
that A
> > is a subClassOf the class that is the intersection of B and C?
> 
> Yes.
> 
> > Should it infer that A is a subClassOf the class that is the
subClassOf
> B and
> > C?
> 
> No. A is just one of the possible subclasses of both B and C. In fact,
you
> may have D as a subClassOf B and C, and D being not necessarily equal
to
> A.
> So, THE class that is the subClassOf B and C does not exists, since it
is
> not unique.
>
> > etc?
> 
> ?

By "etc?", I meant that there seem to be an infinite number of
equivalent descriptions of the same class. For example, aren't these all
equivalent?

- A is a subClassOf B and C
- A is a subClassOf a class that is the intersectionOf B and C
- A is a subClassOf a class that is the intersectionOf B and a class
that is the intersectionOf C
- A is a subClassOf a class that is a subClassOf B and C
- ...

Would a reasoner be expected to decide that any one entails any of the
others? Or just that they ultimately all result in the same subClassOf
relationships on A? The former seems a difficult task for a rules-based
reasoner (because you end up inferring an infinite chain of subClassOf
relationships).

> cheers
> -- e.
> 
> Enrico Franconi                  - franconi@inf.unibz.it
> Free University of Bozen-Bolzano - http://www.inf.unibz.it/~franconi/
> Faculty of Computer Science      - Phone: (+39) 0471-315-642
> I-39100 Bozen-Bolzano BZ, Italy  - Fax:   (+39) 0471-315-649

Thanks,

Geoff
Received on Sunday, 30 March 2003 13:40:04 GMT

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