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Re: "sameAs" error in OWL Language Reference 31 March 2003

From: Jim Hendler <hendler@cs.umd.edu>
Date: Thu, 19 Jun 2003 17:20:43 -0400
Message-Id: <p05200f0fbb17d829981b@[10.0.1.2]>
To: "Richard H. McCullough" <rhm@cdepot.net>, "Guus Schreiber" <schreiber@cs.vu.nl>
Cc: <public-webont-comments@w3.org>

At 2:03 AM -0700 5/8/03, Richard H. McCullough wrote:
>I consider that response to be unsatisfactory.
>"Identity" is the most basic concept in logic.
>OWL should be able to express "identity" directly,
>instead of having to prove it.


Richard - I am a bit confused about this comment.  I agree with what 
you say above, but you are bringing up this problem in the context of 
as RDFS description of owl -- and RDFS has no way to directly express 
identity (other than using the same URI) instead one must create 
something like what we have done below -- making two things 
subproperties of each other.  In OWL we would be able to do what you 
want, but the appendix you are asking about was designed to be an 
RDFS document.  That is, Owl certainly has the ability to express 
identity directly.  For example, I can say

:JohnKennedy a person.
:JackKennedy a person.
:JohnKennedy owl:sameAs :JackKennedy.

So I see that we can do exactly what you ask, we just can't put it 
into the appendix you're asking it to go in, because that appendix is 
written in the less expressive RDFS
  - Jim Hendler





>============
>Dick McCullough
>knowledge := man do identify od existent done;
>knowledge haspart proposition list;
>----- Original Message -----
>From: "Guus Schreiber" <schreiber@cs.vu.nl>
>To: "Richard H. McCullough" <rhm@cdepot.net>
>Cc: <public-webont-comments@w3.org>
>Sent: Thursday, May 08, 2003 1:52 AM
>Subject: Re: "sameAs" error in OWL Language Reference 31 March 2003
>
>
>>  Richard H. McCullough wrote:
>>
>>   > Section 5.2 says sameAs is a synonym for sameIndividualAs
>>   >
>>   > Appendix B says sameAs is a subProperty of sameIndividualAs
>>
>>  Thanks for your comment and for reviewing our documents.
>>  Appendix B indeed defines sameAs as a subproperty of sameIndividualAs,
>>  but also the inverse: sameIndividualAs is defined as a subproperty of
>>  sameAs:
>>
>>  [[
>>  <rdf:Property rdf:ID="sameIndividualAs">
>>     <rdfs:label>sameIndividualAs</rdfs:label>
>>     <rdfs:domain rdf:resource="#Thing"/>
>>     <rdfs:range rdf:resource="#Thing"/>
>>     <rdfs:subPropertyOf rdf:resource="#sameAs"/>
>>  </rdf:Property>
>>
>>  <rdf:Property rdf:ID="sameAs">
>>     <rdfs:label>sameAs</rdfs:label>
>>     <rdfs:subPropertyOf rdf:resource="#sameIndividualAs"/>
>>  </rdf:Property>
>>  ]]
>>
>>  The combination of these two subproperty statements implies that the
>>  extensions of sameAs and sameIndividualAs are identical.
>>
>>  Please let us know whether this response is satisfactory.
>>
>>  Thanks again for your comment,
>>  Guus Schreiber
>>
>>   >
>>   > ============
>>   > Dick McCullough <mailto:rhm@cdepot.net>
>>   > knowledge <http://rhm.cdepot.net/> *:=* man *do* identify *od*
>>  existent *done;*
>>   > knowledge <http://www.volcano.net/~rhm/knowledge> *haspart*
>>  proposition list;
>>
>>
>>  --
>>  NOTE: new affiliation per April 1, 2003
>>
>>  Free University Amsterdam, Computer Science
>>  De Boelelaan 1081a, 1081 HV Amsterdam, The Netherlands
>>  Tel: +31 20 444 7739/7718
>>  E-mail: schreiber@cs.vu.nl
>>  Home page: http://www.cs.vu.nl/~guus/ [under construction]
>>
>>

-- 
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)
http://www.cs.umd.edu/users/hendler      *** NOTE CHANGED CELL NUMBER ***
Received on Thursday, 19 June 2003 17:20:58 GMT

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