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Re: log:forSome/#rdfms-identity-anon-resources

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 3 Jul 2001 10:22:27 -0700
Message-Id: <v04210106b767412aac88@[130.107.66.237]>
To: Dan Connolly <connolly@w3.org>
Cc: w3c-rdfcore-wg@w3.org
>Frank Manola wrote:
> > Dan Connolly wrote:
>[...]
> > > [[[
> > > 4. A person is between a rock and a hard place.
> > > [...]
> > >
> > > Following is the KIF representation:
> > >
> > > (exists ((?x person) (?y rock) (?z place) (?w hard))
> > >         (and (betw ?y ?z ?x) (attr ?z ?w)))
> > > ]]]
> > >
> > > --        Conceptual Graph Examples
> > > http://www.bestweb.net/~sowa/cg/cgexampw.htm#Ex_4
> > > Thu, 22 Mar 2001 01:45:12 GMT
> > > linked from http://www.bestweb.net/~sowa/cg/
> > > linked from http://www.w3.org/DesignIssues/CG#[2]
> >
> > Yes, that was the interpretation I'd been assuming as well (see my
> > message
> > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Jun/0326.html)
>
>Ah... good... then we're agreed, on the essential point.
>
>[...]
>
> >  So I don't understand how queries come into
> > this.
>
>Then never mind; somebody was convinced by the bookseller
>scenario about the need for existentials in RDF, so I thought
>I'd try it here. But I don't need the WG to agree with
>the bookseller/query scenario; only with the interpretation
>of triples as (exists (?a1 ?a2 ...) (and (p1 s1 ?a1) ...) ).

Fine. But then I return to my claim that existentials (at top level 
in assertions) convey exactly the same information as their 
skolemisation. It isnt technicaly correct to say that they entail or 
are equivalent to their skolem form (they arent since they use 
different vocabularies), but they are what might be called 
*effectively* equivalent, in that anything that can be inferred from 
one, that doesnt use the Skolem name, can be inferred from the other. 
In the bookseller example, if you tell the bookseller the skolem 
form, then he does indeed know something that he wouldnt know if you 
told him the existential: he knows that you call the book that you 
want something like "gen4327". But that isnt of much use to him, 
since he doesn't know anything about gen4327 that he couldnt have 
inferred from the existential.

Pat

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Received on Tuesday, 3 July 2001 13:25:22 EDT

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