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Re: AllDisjoint in RDF mapping

From: Jim Hendler <hendler@cs.umd.edu>
Date: Fri, 23 Feb 2007 12:21:33 -0500
Message-Id: <p06240814c204d26ae3b4@[]>
To: ewallace@cme.nist.gov, public-owl-dev@w3.org

At 10:44 AM -0500 2/23/07, ewallace@cme.nist.gov wrote:
>Jim Hendler wrote:
>>Let me join Matthew in requesting this - note also that
>>"DisjointUnion" doesn't answer this need in all cases - often we want
>>to make things disjoint that either belong to many different classes
>>or that we have disjunction of classes without wanting to imply that
>>it is in some way complete.
>>   -JH
>+1  on adding an AllDisjoint construct
>DisjointUnion supports a common pattern used in a number of modeling
>languages (including UML and EXPRESS), and no one from WebOnt would be
>surprised that I am in favor of including it in OWL 1.1.  However, just
>as Jim points out, there are many cases where one wants to specify
>disjointness across a set of classes which don't make up a complete
>covering.  Many new OWL users are surprised that classes aren't disjoint by
>default.  Once they get over this, they start looking for constructs in
>the language like DisjointUnion and AllDisjoint.

actually, I do have a little problem with disjointUnion - the problem 
is that this would be the first OWL feature (I think) that combines 
two definitions at the same time -- so if I say

Class A == DisjointUnion (B,C,D)     (with the obvious meaning, no 
syntax implied)

then I am asserting both the definition of Class A AND the fact that 
B,C, and D are disjoint.  From a human point of view, I wonder if it 
isn't better to avoid the syntactic sugar and have this remain as two 

Class A= Union(B,C,D)

just seems to me that the clarity in the modeling would be clearer

How can you be in two places at once if you're not anywhere at all?
						(Firesign Theatre, 1969)
Prof James Hendler				http://www.cs.rpi.edu/~hendler
Tetherless World Constellation Chair		301-405-2696 (work)
Computer Science Dept			301-405-6707 (Fax)
Rensselaer Polytechnic Institute, Troy NY 12180
Received on Friday, 23 February 2007 17:22:14 UTC

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