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The isAlso rdfs:ConstraintProperty

From: Jonas Liljegren <jonas@paranormal.se>
Date: Tue, 20 Jun 2000 12:05:45 +0200
Message-ID: <394F41F9.457627E1@paranormal.se>
To: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>, RDF Intrest Group <www-rdf-interest@w3.org>
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 !

It seems that way, but it is not.

As an example:

A_Class
    type rdfs:Class
    isAlso B_Class

B_Class
    type AbstractClass

C_Class
    subClassOf B_Class

a_object
    type A_Class
    type C_Class

The object follow the constraint introduced by beeing an instance of
A_Class.  The constraint is that it also has to be _some_type_of_
B_Class. But it doesn't say what class.

If A_Class was a subClassOf B_Class, you had no way of saying that
that objecyt also should be of type C_Class or some other subClassOf
B_Class.



This may not be the ususal way to solving this problem. But I like the
freedom of inventing my own OO. :-)

-- 
/ Jonas  -  http://paranormal.se/myself/en/index.html
Received on Tuesday, 20 June 2000 06:04:09 GMT

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