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Re: Reification

From: <jos.deroo.jd@belgium.agfa.com>
Date: Sun, 8 Apr 2001 13:24:47 +0100
To: GK@ninebynine.org
Cc: www-rdf-logic@w3.org
Message-Id: <OF49F987C2.0823729C-ON41256A28.00437A62@bayer-ag.com>

something I forgot to mention is that in many cases one can avoid
negation take for instance the property :sibling
one cannot be sibling of oneself
but instead of saying {:sibling1 :equals :sibing2} a log:Falsehood.
one can assume :sibling an irreflexive property
in my opinion it's good to be explicit about reflexivity of relations
i can go from paris to paris and the proof is like a
*reflection* about what's connected around paris
(we are thinking about that as *e-circularities*, how you
write the letter e, you make a kind of cycle but you never
use a stepwise piece twice)

so irreflexivity is saying that subject and object are
different (avoiding to write that as a negation)

GK@ninebynine.org@INTERNET@w3.org on 04/08/2001 10:29:34 AM

Sent by:  www-rdf-logic-request@w3.org

cc:   www-rdf-logic@w3.org@INTERNET
Subject:  Re: Reification
At 10:42 PM 4/6/01 +0100, jos.deroo.jd@belgium.agfa.com wrote:
>ps you seem to have some interesting points about negation, but I have
>    to re-read them (as I was close to the belief that open-world-negation
>    was impossible)

Until this, I never got any sense that open world negation was
impossible.  Rather that it always brought the possibility of contradictory
or inconsistent expression.  If I get this right, closed worlds have a
possibility of setting rules on "valid" expressions such that no two such
"valid" expressions are contradictory.

Refering to the 1-pager on formal systems that Dan cited a while ago:

% Formal Systems - Definitions
% (from Ruth E. Davis, Truth, Deduction, and Computation.
% New York: Computer Science press, 1989.)
% (c) Charles F. Schmidt
% Last Modified: Saturday, May 08, 1999 9:07:08 PM GMT

I think this view of a "closed world" might be similar to a "theory".


Graham Klyne
Received on Sunday, 8 April 2001 07:24:57 UTC

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