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Re: nature of anon resource [was Re: log:forSome]

From: Martyn Horner <martyn.horner@profium.com>
Date: Mon, 18 Jun 2001 16:34:05 +0200
Message-ID: <3B2E115D.FB656458@profium.com>
To: fmanola@mitre.org
CC: Brian McBride <bwm@hplb.hpl.hp.com>, jos.deroo.jd@belgium.agfa.com, w3c-rdfcore-wg@w3.org
And 2 centimes from me...

Frank Manola wrote:
> ...
> Here, the resource is represented by an existentially quantified
> variable x.  Skolemization essentially says (ignoring scope issues that
> don't come up in this example) you can give the thing referred to by the
> existentially quantified variable a distinct name, use that name, and
> delete the quantifier. So if I give that resource a URI (or a gensym),
> or it already has one, I've essentially Skolemized it.  In both cases,
> though, we're not talking about an "unknown" in the sense of an
> equation:  the resource isn't unknown (I'm asserting one exists;  it's
> this one right here), even though its identifier may be.
> 

The sense of the Skolemization of the `unknown' resource is surely that
is is given an identification which is in the `global' scope. The space
in which it is said to exist (in the normal understanding of Ora's
example) is the entire web. The `unknown resource' isn't a free variable
in any sense. It is existentially quantified by the RDF segment but to
Skolemize it you have to give it a global identification. Thus one
imagines it has a real but unknown URI only because of one's intuitive
understanding of the need to remove the existential quantification. It
begs the question of how you would form this unknown URI.

The essence of the Skolemization (do I have to type that word again?) is
that the identifier be `new', which is what URIs do for yer every time.

Not particularly clear, I guess: I'm trying to express the natural
feeling that a `definition by properties' gives an anonynous resource a
claim to a global identification. This may be the intuitive reading of
the Skolemization process in the web scope.

-- 
Martyn Horner <martyn.horner@profium.com>
Profium (former name Pro Solutions), Les Espaces de Sophia,
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Tel. +33 (0)4.93.95.31.44 Fax. +33 (0)4.93.95.52.58
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Received on Monday, 18 June 2001 10:34:11 EDT

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