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Re: less-restrictive range and domain terms

From: David Menendez <zednenem@psualum.com>
Date: Tue, 04 May 2004 16:28:47 -0400
To: Phil Dawes <pdawes@users.sf.net>
Cc: Jeremy Carroll <jjc@hplb.hpl.hp.com>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, b.fallenstein@gmx.de, pdawes@users.sourceforge.net, www-rdf-interest@w3.org
Message-id: <r02000200-1033-A5DD5FD49E0911D8AC0B000393758032@[10.0.1.2]>

Phil Dawes writes:

> 
> Jeremy Carroll writes:
>  > 
>  > What about
>  > 
>  >   x:schnack phil:rangeIncludes y:Ghostly
>  > ===>
>  >   _:a x:schnack _:b .
>  >   _:b rdf:type y:Ghostly .
>  > 
> 
> Actually that was the inference I was trying to avoid. Unless I'm
> mistaken it effectively forces all resources that are objects in a
> triple with property x:schnak to be of rdf:type y:Ghostly.  
> (as rdfs:range does).

I think Jeremy was thinking in terms of existential quantification,
rather than universal. Something like, "There is a resource Y that is
the object of x:schnack and an instance of y:Ghostly."

That is:

    rdfs:range(x:schnack, y:Ghostly) ->
        forall X, Y. x:schnack(X,Y) -> y:Ghostly(Y)
    
    phil:rangeIncludes(x:schnack, y:Ghostly) ->
        exists X, Y. x:schnack(X,Y) & y:Ghostly(Y)

-- 
David Menendez <zednenem@psualum.com> <http://www.eyrie.org/~zednenem/>
Received on Tuesday, 4 May 2004 16:29:40 GMT

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