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Proposed response to http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0027.html

From: Guus Schreiber <schreiber@cs.vu.nl>
Date: Thu, 08 May 2003 11:54:21 +0200
Message-ID: <3EBA294D.6080207@cs.vu.nl>
To: WebOnt WG <www-webont-wg@w3.org>

I answered the initial comment directly, because it seemed to require 
just an explanation of our documents. I enclose my proposed second reply 
for review by the WG.

I think an OWL ontology of OWL itself could be useful, but probably best 
as some note at a later point in time.

Guus

Proposed response to:
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0027.html

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.

OWL can express that two resources have the same "identity", using 
owl:same(Individual)As, see the Clinton example in Sec. 5.2.

Appendix B is a metamodel of OWL expressed in RDF Schema. The notion of 
identity cannot be expressed in RDF Schema, therefore we used a weaker 
notion (same extension, see previous reply) to define the relationship 
between sameAs and sameIndividualAs.

If we had constructed an OWL ontology of OWL, we could have said:

   owl:sameAs owl:sameAs owl:sameIndividualAs .

Our current definition in RDF Schema could have been been expressed in 
OWL as:

   owl:sameAs owl:equivalentProperty owl:sameIndividualAs .

Please let us know whether this response  is satisfactory.

Thanks again for your comment,
Guus Schreiber

 > ============
 > 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

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.

OWL can express that two resources have the same "identity", using 
owl:same(Individual)As, see the Clinton excample in Sec. 5.2.

Appendix B is a metamodel of OWL expressed in RDF Schema. The notion of 
identity cannot be expressed in RDF Schema, therefore we used a weaker 
notion (same extension, see previous reply) to define the relationship 
between sameAs and sameIndividualAs.

If we had constructed an OWL ontology of OWL itself, we could have said:

   owl:sameAs owl:sameAs owl:sameIndividulAs .

Our current defenition in RDF Schema could have been been expressed in 
OWL as:

   owl:sameAs owl:equivalentPropertyAs owl:sameIndividulAs .

Please let us know whether this reponse  is satisfactory.

Thanks again for your comment,
Guus Schreiber



 > ============
 > 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;
 >>
Received on Thursday, 8 May 2003 05:54:22 GMT

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