RE: Logic and Using The Semantic Web Toolbox

Hello,

	sorry, I am late to answer, but:

in his message (RE: Logic and Using The Semantic Web Toolbox) of 12/12/00,
Peter F. Patel-Schneider wrote:
>I fear that parts of RDF are not suitable for this purpose.  In particular,
>RDF already includes some ``semantic'' stuff, namely sets and reification,
>that has a very shakey semantic status.  Sure, it is possible to produce
>something at the next layer up that maps into RDF in some way.  But this
>next layer will not be able to build on the shakey portions of RDF.
>
>As an example, suppose I want to include sets in my version of the next
>layer.  How am I to do this?  I have to make a whole bunch of choices about
>how my sets will work (see below).  If I use the RDF syntax for sets, then
>these choices will impact RDF sets.  In essence, I will be imposing my view
>of sets onto RDF sets, which does not seem to be a valid way of extending
>RDF.
>
>I don't see how you can add semantics to constructs that already exist.  If
>the constructs already exist, then they should have a meaning.  Semantic
>extensibility should involve adding new constructs with their own meanings.

	I always hit the same nail: this is the way ontologies will 
be "extended" with the current DAML-ONT/OIL technology. Since there 
is no way to declare illegal extensions of a concept people can 
extend (read restrict) them "imposing" their new semantics to the old 
concepts... and everybody seems to be fine with it.
-- 
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