bNodes as local constants

Dear all,

As fulfillment of my example to show that we cannot simply treat bNodes
as local constants, here is a very simple example.


In RDF we have

john rdf:type Person   entails   _:x rdf:type Person

where _:x is a bNode. The entailment relationship holds because there is
an assignment for _:x which is the same as the   interpretation of the
constant john.


If we would translate _:x to a local constant, say, x, then this
entailment relation no longer holds:

john rdf:type Person   not-entails   x rdf:type Person

Although john and x may denote the same individual in some
interpretation, this is by no means the case in every interpretation
which is a model of    john rdf:type Person.


Best, Jos

-- 
Jos de Bruijn,        http://www.debruijn.net/
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When we remember we are all mad, the mysteries 
disappear and life stands explained.
  - Mark Twain