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Re: Conventions and top-level ontologies for RDF

From: Charles McCathieNevile <charles@w3.org>
Date: Tue, 20 Jun 2000 03:30:50 -0400 (EDT)
To: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
cc: Jonas Liljegren <jonas@paranormal.se>, RDF Intrest Group <www-rdf-interest@w3.org>
Message-ID: <Pine.LNX.4.20.0006200329040.10273-100000@tux.w3.org>
This is almost it - if A is a subclass of B AND B is a subclass of A then A
isAlso B.

charles McCN

On Tue, 20 Jun 2000, Pierre-Antoine CHAMPIN wrote:

  Jonas Liljegren wrote:
  > ** isAlso
  > 
  > I have also found the need to say that objects of a certain type must
  > also be of certain other type. That is: a instance with multiple
  > classes. Not a class that inherits from many classes.
  > 
  > isAlso  -  A resource of this type must also be a of that other type
  >     type rdfs:ConstraintProperty
  >     domain rdfs:Class
  >     range rdfs:Class
  
  this is exactly the same :
  suppose class A isAlso B
  then any instance of A is an instance of B,
  then A is *structurally* a subclass of B !
  
  bringing in into pseudo logical rules, this is exactly the same :
  
  I type B :- I type A, A subClassOf B
  I type B :- I type A, A isAlso B
  
  or did I misunderstood one of the properties meaning ?
  
  > The purpose is to represent in an RDF Schema, the properties a
  > specific satement can have.
  > 
  > Implementation
  > --------------
  > 
  > StatementConstraint
  >     subClassOf rdfs:ConstraintProperty
  > 
  > statementPredicate
  >     type StatementConstraint
  >     domain rdfs:Statement
  >     range rdf:predicate
  > 
  > Illustration
  > ------------
  > 
  > intrest
  >     type rdf:predicate
  >     domain Person
  >     range Topic
  > 
  > IntrestStatement
  >     subClassOf rdf:Statement
  >     statemetPredicate intrest
  > 
  > strength
  >     type rdf:predicate
  >     domain IntrestStatement
  >     range FloatZeroToOneInclusive
  
  your example is not valid :
  IntrestStatement is not a statement : it is a class ;
  therefore, the domain of statementPredicate is not Statement, but Class,
  even if you intend to use it only on classes that are subclasses of the Statement class...
  
  looks like you are trying to provide RDF statements with Descrition Logic features :
  describing a class in terms of constraints upon its instances...
  
  have a look at OIL (http://www.cs.vu.nl/~dieter/oil/oil.nutshell.pdf),
  you may find it interesting...
  
    Pierre-Antoine
  --- Quid quid Latine dictum sit, altum viditur
      Whatever is said in Latin sounds important.
  

--
Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
Location: I-cubed, 110 Victoria Street, Carlton VIC 3053
Postal: GPO Box 2476V, Melbourne 3001,  Australia 
Received on Tuesday, 20 June 2000 03:30:59 GMT

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