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Re: GUIDE: New version.

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 20 Sep 2002 09:33:07 -0400 (EDT)
Message-Id: <20020920.093307.101246530.pfps@research.bell-labs.com>
To: michael.smith@eds.com
Cc: www-webont-wg@w3.org

I read over the first part of the Guide and have a few comments:

1/ It is indeed *very* easy to create sound reasoning systems.  As Ian has
   pointed out a completely comatose system is a sound reasoner for most
   languages.  A sound and *useful* reasoner is much more difficult to
   build and a sound and *complete* reasoner is generally even more

2/ Is RDFS ``very general''?  I'm not convinced that it is.  I would much
   prefer a different description of RDFS's lack of commitments.

3/ The mentions of OIL and DAML-ONT are not particularly informative.  It
   would be much better, in my view, to either shorten or expand this bit
   of the guide.  As suggestions for changes are supposed to be accompanied
   by new working, I enclose new, expanded wording that I think is much more
   informative, and closer to how events actually played out.


Suggested new text:

<a href="http://www.w3.org/TR/REC-rdf-syntax">The Resource Description
Framework (RDF)</a> was the first language specified by the W3C for
representing semantic information about arbitrary resources.
<a href="http://www.w3.org/TR/CR-rdf-schema">RDF Schema (RDFS)</a> 
is a W3C candidate recommendation for an extension to RDF to describe RDF
RDFS can be used to create ontologies, but it is purposefully very
lightweight so little can be said about the consituents of ontologies in
Further, RDF and RDFS had only an informal specification of the meaning of
their constructs.

Like OWL, RDFS includes classes and properties, as well as 
range and domain constraints on properties.  It provides
inheritance hierarchies for both classes and properties.  Upon its
release users began requesting additional features, including data
types, enumerations and the ability to define properties more

At about the same time as RDFS was being developed,
a group of European researchers, funded through the
<a href="http://www.ontoknowledge.org/">On-To-Knowledge project</a> of the
E.U., defined an ontology language called  
<a href="http://www.ontoknowledge.org/oil/index.shtml">OIL
(Ontology Inference Layer)</a>. 
OIL was based on ideas from 
<a href="http://dl.kr.org">description logics</a>,
and the W3C XML and RDF (including RDFS) languages.
OIL was much more powerful than RDFS, but tried to retain some
compatability with RDF and RDFS.
The basic syntax for OIL was a frame-like syntax, but there was also an
RDFS syntax for OIL. 
OIL was equipped with a full model-theoretic semantics, providing a formal
meaning for the language.

In an attempt to extend the expressive power of RDFS,
a group of U.S. researchers, funded through the 
<a href="http://www.daml.org/">DAML (DARPA Agent Markup
Language) program</a> initiated by the U.S. Defense Advanced Research Projects
Agency, defined a language called 
<a href="http://www.daml.org/2000/10/daml-ont.html">DAML-ONT</a>.  
This language was also an ontology language, somewhat similar to OIL, but
based much more directly on RDFS.  
The basic syntax for DAML-ONT was the RDF syntax.
A <a href="http://www.daml.org/2000/10/DAML-Ont-kif-axioms-001107.html">
partial axiomatization</a> in KIF was provided form DAML-ONT.

Instead of continuing with separate ontology languages for the Semantic
Web, a group of researchers, including many of the main participants in
both the OIL and DAML-ONT efforts, got together in the 
<a href="http://www.daml.org/committee/">Joint US/EU ad hoc Agent Markup
Language Committee</a> to create a new web ontology language.
This language 
<a href="http://www.daml.org/2001/03/daml+oil-index.html">DAML+OIL</a>
builds on both OIL and DAML-ONT, and was 
<a href="http://lists.w3.org/Archives/Public/www-webont-wg/2001Dec/0144.html">submitted</a>
to the W3C as a proposed 
basis for OWL and was subsequently selected as the starting point for OWL.
Received on Friday, 20 September 2002 09:33:27 UTC

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