- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Mon, 28 Apr 2003 08:43:31 -0400 (EDT)
- To: heflin@cse.lehigh.edu
- Cc: www-webont-wg@w3.org
To: heflin@cse.lehigh.edu Cc: www-webont-wg@w3.org Subject: Re: Possible confusion in Reference From: Peter F. Patel-Schneider <pfps@research.bell-labs.com> Fcc: +Outgoing In-Reply-To: <3EA9A30B.6A6C702E@cse.lehigh.edu> References: <3EA9A30B.6A6C702E@cse.lehigh.edu> X-Mailer: Mew version 2.2 on Emacs 21.1 / Mule 5.0 (SAKAKI) ---- From: Jeff Heflin <heflin@cse.lehigh.edu> Subject: Possible confusion in Reference Date: Fri, 25 Apr 2003 17:05:15 -0400 > > I was looking through the reference today and I think the description of > owl:sameAs in section 5.2 is misleading. It says: > > In OWL Full, where class can be treated as instances of (meta)classes, > we can use the owl:sameAs construct to define class equality, thus > indicating that two concepts have the same intensional meaning. > > (btw, note "where class can" should be "where classes can") > > I believe that in fact sameAs has an even stronger interpretation: that > the classes are the same resource! (Peter, please correct me if I'm > wrong here). This is correct. owl:sameAs (and owl:sameIndividualAs) provides co-denotation. > Note the implications of this. If one class has some > meta-property, such as author, label, last change date or whatever, then > any class that is "sameAs" it also has the same values for those > properties. Correct. > Chances are, this is not what is usually intended. Hmm. Sometimes it is, at least for those who think in RDF. > However, > the reference implies this is the preferred way to map two class > concepts that have the same intensional meaning. Unfortuantely, OWL > doesn't really have a mechanism for truly stating that two classes have > the same intensional meaning. How about owl:equivalentClass? > That would require us to somehow separate > meta-properties that are about a particular resource from those about > the concept it denotes. I'm not sure that OWL makes the distinction you describe here. However, there is a difference between the resource denoted by a URL and the class extension of this resource. owl:equivalentClass equates the latter without affecting the former. owl:sameAs and owl:sameIndividualAs equate the former (and thus also equate the latter). > Anyway, I think this issue should be explained > and <footballTeam owl:equivalentClass us:soccerTeam /> should be the put > forth as the preferred way for mapping these two classes. It depends on what you want. (I tend to view owl:equivalentClass as the preferred mechanism, but I realize that others may differ.) > Jeff peter
Received on Monday, 28 April 2003 08:43:42 UTC