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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).

[...]

peter
Received on Monday, 31 March 2003 08:55:53 GMT

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