- 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
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 To: Jos De_Roo/AMDUS/MOR/Agfa-NV/BE/BAYER@AGFA 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.) % http://www-rci.rutgers.edu/~cfs/305_html/Deduction/FormalSystemDefs.html % (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". #g ------------ Graham Klyne GK@NineByNine.org
Received on Sunday, 8 April 2001 07:24:57 UTC