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Re: Strange behaviour of datatypes test A1 with answer yes and literals untidy

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Tue, 16 Jul 2002 11:13:19 -0400 (EDT)
Message-Id: <200207161513.g6GFDJG02223@pantheon-po04.its.yale.edu>
To: www-rdf-logic@w3.org

   [Brian McBride]
   With reference to Drew's message:


   Consider datatypes test A1 with answer YES and literals untidy (i.e. A2 and 
   A3 NO).

   We have:

      <bag1> rdf:_1 "10" .         (1)
      <bag2> rdf:_1 "10" .         (2)
      <bag1> rdf:_1 _:l .          (3)
      <bag2> rdf:_1 _:l .          (4)

I don't see why (1) and (2) entail (3) and (4).  We've agreed that
literals without datatyping information could mean anything at all.
So how can we conclude that the first "10" denotes the same thing as
the second "10"?

   We have a cardinality constraint of max 1 on rdf:_1.

   Now add some new triples:

      <bag1> rdf:_1 _:a1 .
      _:a1   <foo:decimal> "10" .

   This is consistent with (1) above and the cardinality constraint, and also add:

      <bag2>  rdf:_1 _:a2 .
      _:a2    <foo:binary>  "10" .

   This is consistent with (2) above and the cardinality constraint.

   All together the added statements are consistent with (1) and (2) above, 
   but not with with (3) and (4) above.

Yes, they're inconsistent, which shows that the entailment was incorrect.

   This is not, as I first thought, non-monotonic.  However, would you agree 
   that the entailment given above creates a contradiction where we should not 
   really have one?

Yes it creates a contradiction, but I am no longer tempted to conclude
(3) and (4) from (1) and (2).

                                             -- Drew
Received on Tuesday, 16 July 2002 11:13:26 UTC

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