- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Mon, 10 Mar 2003 10:52:13 -0500 (EST)
- To: nogievet@cogx.com
- Cc: costello@mitre.org, www-rdf-logic@w3.org
From: "Nikita Ogievetsky" <nogievet@cogx.com> Subject: Re: Treating a class as both an individual and a class? Date: Mon, 10 Mar 2003 07:40:31 -0800 > > ----- Original Message ----- > From: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com> > To: <nogievet@cogx.com> > Cc: <costello@mitre.org>; <www-rdf-logic@w3.org> > Sent: Monday, March 10, 2003 7:27 AM > Subject: Re: Treating a class as both an individual and a class? > > > > From: "Nikita Ogievetsky" <nogievet@cogx.com> > > Subject: Re: Treating a class as both an individual and a class? > > Date: Mon, 10 Mar 2003 07:24:08 -0800 > > > > > Peter F. Patel-Schneider wrote: > > > > No, this is not good modelling. If you want to say that Davenport has > a > > > > River, you should say so, via > > > > > > > > <City rdf:ID="Davenport"> > > > > <rdfs:subClassOf> > > > > <owl:Restriction> > > > > <owl:onProperty rdf:resource="hasFeature" /> > > > > <owl:someValuesFrom rdf:resource="http://geodesy.org#River"/> > > > > </owl:Restriction> > > > > </rdfs:subClassOf> > > > > .... > > > > </City> > > > > > > > > > > Hmmm.... > > > Peter, in your example an individual city is a class? > > > > No, Davenport is an instance of the class City. > > Sorry, I am missing this: do you agree with me or not? > How can rdfs:subClassOf be used to denote "instance of" > Should not "rdf:Type" be used instead (as I am trying to do bellow)? Sorry, you are correct. I messed up. > > > Should not it be something like: > > > > > <CityOnARiver rdf:ID="Davenport"> > > > .... > > > </CityOnARiver> > > > > > > <owl:Class rdf:ID="CityOnARiver"> > > > <rdfs:subClassOf rdf:resource="#River"> > > > <rdfs:subClassOf> > > > <owl:Restriction> > > > <owl:onProperty rdf:resource="hasFeature" /> > > > <owl:someValuesFrom rdf:resource="http://geodesy.org#River"/> > > > </owl:Restriction> > > > </rdfs:subClassOf> > > > </owl:Class> > > > > This makes a city on a river be a river, which is probably not what is > > wanted. > > It is a typo, of course: I meant: > <rdfs:subClassOf rdf:resource="#Class"> I was concentrating too much on your mistake, and not on mine. > <rdfs:subClassOf rdf:resource="#Class"> is still incorrect as it makes CityOnARiver a meta-class, and Davenport would still be a class. The correct method would be <CityOnARiver rdf:ID="Davenport"> .... </CityOnARiver> <owl:Class rdf:ID="CityOnARiver"> <rdfs:subClassOf> <owl:Restriction> <owl:onProperty rdf:resource="hasFeature" /> <owl:someValuesFrom rdf:resource="http://geodesy.org#River"/> </owl:Restriction> </rdfs:subClassOf> </owl:Class> In OWL you could do other interesting things then 1/ <CityOnARiver rdf:ID="Davenport"> .... </CityOnARiver> makes Davenport a city that has a river as a feature (without saying which one it is). 2/ <http://geodesy.org#River" rdf:ID="YYYRiver" /> <City rdf:ID="Davenport"> <hasFeature rdf:resource="#YYYRiver" /> </City> makes Davenport a city on the YYYRiver and also an instance of CityOnARiver (without mentioning CityOnARiver explicitly). > --Nikita. peter
Received on Monday, 10 March 2003 10:52:25 UTC