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Re: Proposed response to: Missing AllSame

From: Jim Hendler <hendler@cs.umd.edu>
Date: Mon, 16 Jun 2003 10:08:42 -0400
Message-Id: <p05200f43bb137fe3012d@[]>
To: Guus Schreiber <schreiber@swi.psy.uva.nl>, WebOnt WG <www-webont-wg@w3.org>

At 3:25 PM +0200 6/16/03, Guus Schreiber wrote:
>Ron Alford wrote:
>>  Hello,
>>  Since there is an owl:AllDifferent, why is there not an 
>>owl:AllSame?  I have a need for it on my current project.  It would 
>>be nice for it to have similar semantics to owl:AllDifferent.
>>  Thanks,
>>    - Ron Alford
>>  --
>>  Ron Alford, KB0NUV
>>  http://volus.net/~ronwalf
>Thanks for your comment.
>We introduced a AllDifferent construct because of the exponential 
>growth of the number of differentFrom statements; see Sec. 6.3 of 
>OWL Reference [1]
>For ontologies in which the unique-names assumption holds, the use 
>of owl:differentFrom is likely to lead to a large number of 
>statements, as all individuals have to be declared pairwise disjoint.
>The case is different for sameAs, because sameAs only leads to 
>linear growth of the number of statements. (due to the transitive 
>nature of sameAs, the statements "a sameAs b" and "b sameAs c" 
>already imply "a sameAs c").
>Please respond, copying public-webont-comments@w3.org, as to whether
>you are satisfied with this response.
>Guus Schreiber
>[1] http://www.w3.org/TR/owl-ref/#AllDifferent-def

Looks good.
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  *** 240-277-3388 (Cell)
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Received on Monday, 16 June 2003 10:08:47 UTC

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