W3C home > Mailing lists > Public > www-webont-wg@w3.org > August 2002

semantics, delay, apologies

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 27 Aug 2002 10:14:09 -0700
Message-Id: <p05111b0bb991615b4869@[]>
To: www-webont-wg@w3.org

Guys, I promised to have a revised OWL/RDF document ready by last 
night, but it will be slightly delayed. I hope to have it done by EOB 
today. Sorry about that.

Quick response to all the counterxamples: Yes, Peter is quite right 
that those entailments do not go through with the MT in my earlier 
document. However it is possible to tweak the MT so that they do. The 
key is to make sure that all interpretations contain all the required 
classes inside owl:Class, and the way to do that is to adapt the 
trick I used for the sequences, which is to define the interpretation 
using the owl deductive closure (Essentially the same trick that 
Herbrand used, for those of you who know the FOL completeness 
theorem). The upshot of all this is that OWL/RDF is rather more 
complicated than I thought it had to be; that the OWL/RDF closure 
rules are horrendously complicated; and that it is just about 
impossible to describe OWL/RDF without reference to the abstract 
syntax.  Nevertheless, it does seem to give a genuine layering, ie 
there is no need to darken anything and OWL/RDF turns out to be a 
genuine semantic extension of RDFS.  So the primary question is, I 
would suggest, not whether this is possible, but whether the 
complexity of the OWL-to-RDFS embedding is worth it.

Anyway, full details should be available later today (PT, that is.)


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Received on Tuesday, 27 August 2002 13:15:01 UTC

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