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Re: Existential Quantification [Re: New RDF model theory]

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 27 Aug 2001 11:45:27 -0700
Message-Id: <v04210104b7b04470498f@[130.107.66.237]>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
>In Pat's impressive document I note the following:
>
>As far as I can tell the following two graphs (which I represent in a
>bastardized ntriple) entail one another:
>
>G1:
><a> <b> <c>.
>
>
>G2:
><a> <b> <c>.
>_:x <b> <c>.
>
>
>Have I understood this right?

I would say so, yes, presuming that G2 is considered wellformed.

>If so, is this desired?

Hmmm...why not?

>I am a little confused at the moment about it ...
>
>reading _:x <b> <c>. as existentially quanitifed then it seems trivial that
>G1 and G2 entail one another, whereas the interpolation lemma seems to be
>false.

Ah.  Yes, I hadn't noticed that one can add redundancy. I need to 
state it more carefully. Thanks!!

I think I will strip out all the 'proof theory' from the normative MT 
document and write that up separately. For one thing, it is dragging 
the MT since its easier to write equations than to do proofs :-)

Pat Hayes

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Received on Monday, 27 August 2001 14:44:26 EDT

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