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Re: intersectionOf and subClassOf

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 31 Mar 2003 08:55:42 -0500 (EST)
Message-Id: <20030331.085542.125113561.pfps@research.bell-labs.com>
To: geoff@sover.net
Cc: franconi@inf.unibz.it, www-rdf-logic@w3.org

From: "Geoff Chappell" <geoff@sover.net>
Subject: RE: intersectionOf and subClassOf
Date: Sun, 30 Mar 2003 17:26:30 -0500


> > Yes, if you mean: A is a subClassOf THE class that is the
> intersectionOf B
> > and C
> That would make sense to me, but... I modified that one from THE to A
> based upon Peter Patel-Schneider's comment that "(there can be more than
> one intersection in OWL)". Did I misinterpret that?

No you didn't.  There can be an infinite number of intersections.  For
example, given a list of A and B
	_:l1 rdf:first A .
	_:l1 rdf:rest _:l2 .
	_:l2 rdf:first B .
	_:l2 rdf:rest rdf:nil .
it is *possible* to have any number of (different) OWL classes that are
related to this list via owl:intersectionOf, as in 
	_:i1 owl:intersectionOf _:l1 .
	_:i2 owl:intersectionOf _:l1 .
	_:i3 owl:intersectionOf _:l1 .
However, it is not *required* that there be any more than one of these
intersection classes.

> > > - A is a subClassOf a class that is the intersectionOf B and a class
> > > that is the intersectionOf C
> > 
> > What is "a class that is the intersectionOf B"?

It is possible to have a class that is an intersection of B, as follows:
	_:l3 rdf:first B .
	_:l3 rdf:rest rdf:nil .
	_:iB1 owl:intersectionOf _:l3 .
Again, however, *THE* is not a good idea in this wording.

> I guess I needed some parens or something there - though then you'd
> likely just have asked "What is a class that is the intersectionOf C". I
> meant only:
> <owl:Class>
> 	<owl:intersectionOf rdf:parsetype="Collection">
> 		<owl:Class rdf:about="C"/>
> 	</owl:intersectionOf>
> </owl:Class>
> That's not invalid in owl full, is it? (albeit not very informative)

No, this is perfectly fine in OWL Full (and similar constructions are
possible in OWL DL).


Received on Monday, 31 March 2003 08:55:53 UTC

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