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Re[2]: P.S. re: two senses of Class (RDF vocabulary definiitions)

From: Leonid Ototsky <leo@mmk.ru>
Date: Wed, 20 Nov 2002 13:02:21 +0500
Message-ID: <8543.021120@mmk.ru>
To: "Richard H. McCullough" <rhm@cdepot.net>
CC: "David Menendez" <zednenem@psualum.com>, "RDF-Interest" <www-rdf-interest@w3.org>

Hello Richard,

Wednesday, November 20, 2002, 12:34:09 PM, you wrote:

RHM> Re: P.S. re: two senses of Class (RDF vocabulary definDavid
RHM>  Menendez and Leonid Ototsky both inform me that an Individual can be a Class.
RHM> That is absolutely false.

Sorry, but I said something another !!! Namely that A MEMBER of a CLASS
can be an Individual Type or a CLASS type ( from the EPISTLE Core
Model point of view) . But NOT that "an Individual can be a Class" (?!)


RHM> Here are the definitions from the theory of epistemology,
RHM> paraphrased to match the context of our current discussion.

RHM>     An individual is a single concrete existent.

RHM>     A class is an abstract group of two or more similar individuals.
RHM> ============
RHM> Dick McCullough
RHM> knowledge := man do identify od existent done
RHM> knowledge haspart list of proposition

RHM>   ----- Original Message -----
RHM>   From: David Menendez
RHM>   To: RDF-Interest
RHM>   Sent: Tuesday, November 19, 2002 10:52 PM
RHM>   Subject: Re: P.S. re: two senses of Class (RDF vocabulary definiitions)

RHM>   At 10:16 PM -0800 2002-11-19, Richard H. McCullough wrote:
RHM>     I had forgotten about the other problem with type, e.g.

RHM>         John Doe  type  person

RHM>     where

RHM>         John Doe  individualOf  person

RHM>     not

RHM>         John Doe  subClassOf  person

RHM>   I'm not sure what problem you're seeing.

RHM>   In RDF(S), the statements
RHM>     eg:john_doe rdf:type eg:Person.
RHM>   and
RHM>     eg:john_doe rdf:subClassOf eg:Person.
RHM>   are entirely independent and mean different things.

RHM>   My understanding of RDF-MT is that the first statement means "I(eg:john_doe) is a member of ICEXT(I(eg:Person))" while the second means "ICEXT(I(eg:john_doe)) is a subset of
RHM> ICEXT(I(eg:Person))". These are distinct assertions, and either can be true without the other being true.

RHM>   (I(x) is the interpretation of x, and ICEXT(y) is the set of all things belonging to the class y.)

RHM>   If I say
RHM>     eg:Dog rdfs:subClassOf eg:Mammal.
RHM>   I am not implying
RHM>     eg:Dog rdf:type eg:Mammal.
RHM>   because that would mean that the class "Dog" is a mammal, which it is not. Individual dogs are mammals, but the set of all dogs is a set.
RHM> --
RHM> Dave Menendez - zednenem@psualum.com - http://www.eyrie.org/~zednenem/

Best regards,
mailto:leo@mmk.ru and copy to leo@mgn.ru
Leonid Ototsky,
Chief Specialist of the Computer Center,
Magnitogorsk Iron&Steel Works (MMK)- www.mmk.ru
Received on Wednesday, 20 November 2002 04:59:42 UTC

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