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Re: N3 contexts vs RDF reification

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 03 May 2001 11:24:38 -0400
To: seth@robustai.net
Cc: phayes@ai.uwf.edu, www-rdf-interest@w3.org
Message-Id: <20010503112438J.pfps@research.bell-labs.com>
From: "Seth Russell" <seth@robustai.net>
Subject: Re: N3 contexts vs RDF reification
Date: Wed, 2 May 2001 20:58:43 -0700

> From: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
> Re: http://robustai.net/mentography/TransitiveProperties.gif
> > Pretty pictures might be useful for some things, but they certainly are
> not
> > sufficient to show that your can represent second-order sentences in RDF.
> > Sure you may have a syntactic encoding of second-order sentences in
> > RDF, but you can also have an encoding of second-order sentences in
> > XML or even HTML.  To have a second-order logic, you have to provide a
> > second-order meaning for these encodings, either derived from the meaning
> > of the encoding language or independent of that meaning.  You have done
> > neither.
> Could you perhaps sketch for me what a "second-order meaning" would look
> like?  Maybe, at least, specify what language this 'meaning' is to be
> expressed in and provide an example.   Now, obviously, in my simple diagram
> of Pat's description of transivity ( in KIF, i presume) I did not elaborate
> the rest of the ontology and logical constructs that would complete a
> functional model.  Is your criticism of my diagram that I have not make that
> elaboration?  Wouldn't such a criticism be kind of like criticizing a quick
> sketch of a cartoon character because it didn't animate itself?  Can you not
> see that if the extra assertions necessary to elaborate the modes are in
> fact in the DAML schemas, that they could be easily added to the diagram?
> ... i am very confused as to what you and Pat are requiring?
> Seth

To have a logic, any logic, you need more than syntax.  You need either
some notion of inference or some sort of model theory.  Both are much
beyond what can be explained in a web note.  I strongly suggest reading a
good book on formal logic.  

For examples of what might be required, you could look at the
model-theoretic semantics and the axiomatization of DAML+OIL.

Peter Patel-Schneider
Bell Labs Research.
Received on Thursday, 3 May 2001 11:26:23 UTC

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