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Re: RDF Statements as floating Cons Cells

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Fri, 8 Jun 2001 10:46:03 -0400 (EDT)
Message-Id: <200106081446.f58Ek2s28586@pantheon-po03.its.yale.edu>
To: www-rdf-logic@w3.org

   [Pat Hayes]
   Oh God, I am inclined to give up at this point. Why are we even 
   bothering to try to adapt this unbelievably broken system to make it 
   do something which it is  incapable of doing? I thought that I could 
   see a way to extend RDF to add more complex syntax to it, and now you 
   have convinced me that it can't be done.

   ...
   How does it stop someone adding

   X3a X4b S
   X4b nil T

   and making the structure 'doubly defined' ? There is no way to do 
   that, as far as I can see. At this point I think I shall just go home 
   and go to bed.

Well, I hope a good night's sleep has revived you.

I don't quite see why "double definition" is so scary here and not
elsewhere.  We could have an axiom ruling it out, so that if the same
list were defined twice we could conclude that the CAR in one
definition must = the CAR in the other, and so forth.  We might get a
contradiction out of it.  Or whatever.  But is it any different from
father(fred, sally) and father(murderer(mary), sally)?  We don't
conclude Sally has two fathers, but that fred = murderer(mary).

                                             -- Drew McDermott
Received on Friday, 8 June 2001 10:46:12 GMT

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