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Re: subclasses (RDF vocabulary definitions)

From: Richard H. McCullough <rhm@cdepot.net>
Date: Thu, 21 Nov 2002 16:00:35 -0800
Message-ID: <002401c291ba$2f5d1850$bd7ba8c0@rhm8200>
To: <www-rdf-interest@w3.org>, "David Menendez" <zednenem@psualum.com>, "Brian McBride" <bwm@hplb.hpl.hp.com>
Fair enough.  Let me reprise both the notation and the English.

The notation is
    man iss* animal   means   either  man  is  animal
                                                 or  man  iss  animal

The English is
    When RDFS says that man is a subclass of animal
    what it means is that either (1) the set of all men is identical to the set of all animals
                                         or (2) the set of all men is a proper subset of the set of all animals
============ 
Dick McCullough 
knowledge := man do identify od existent done
knowledge haspart list of proposition

  ----- Original Message ----- 
  From: Brian McBride 
  To: Richard H. McCullough ; www-rdf-interest@w3.org ; David Menendez 
  Sent: Thursday, November 21, 2002 2:41 PM
  Subject: Re: subclasses (RDF vocabulary definitions)


  I must be missing something.  I see notation.  I see no explanation.

  Brian


  At 14:27 21/11/2002 -0800, Richard H. McCullough wrote:
  >Brian said:
  >
  >   [[ll classes are subclasses of themselves.
  ><<this is true, but RDF Schema should use proper subsets instead of subsets.
  >Using subsets logically permits such absurdities as: the set of all men is
  >identical to the set of all animals.>>]]
  >
  >I'm intrigued by that one.  We have a major flaw if that is true.  Care to
  >explain?
  >I'm going to use some KR notation here because I think you will find it 
  >easier to understand.
  >Here's the notation
  >"is":  man  is  animal          sets are identical
  >"iss":  man  iss  animal       man is proper subset of animal
  >"iss*": man  iss*  animal      man is subset of animal
  >
  >iss is the main property used in KR
  >iss* is the rdfs:subClassOf property, and its meaning is that
  >     either man is animal
  >          or man iss animal
  >
  >and it's also the source of "bragging" about a class being a subclass of 
  >itself, i.e.,
  >     man iss* man
  >     animal iss* animal
  >============
  >Dick McCullough
  ><http://rhm.cdepot.net/>knowledge := man do identify od existent done
  >knowledge haspart list of proposition
Received on Thursday, 21 November 2002 19:00:37 GMT

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