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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@[10.173.43.28]>
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.
>
>-Evan



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 
assertions

Class A= Union(B,C,D)
AllDisjoint(B,C,D)

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


-- 
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 GMT

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