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Re: SEM: Light review of semantics document

From: Jeff Heflin <heflin@cse.lehigh.edu>
Date: Thu, 07 Nov 2002 14:21:28 -0500
Message-ID: <3DCABD38.1212403E@cse.lehigh.edu>
To: pat hayes <phayes@ai.uwf.edu>
CC: www-webont-wg@w3.org

Pat, there is a terminology problem here. What you and Peter call
ontologies are different from what I call ontologies. My practical
definition is that OWL ontologies are only those OWL documents that
include the <owl:Ontology> tag. All other OWL documents are not OWL
ontologies. Now, you are correct that a document with <owl:Ontology>
could consist of nothing but ground facts, and as such you don't
technically need to have a separate class of document for data. However,
the fact is, people only use the <Ontology> tag when they are defining
vocabularies (this statement is based on common usage in DAML). Are you
suggesting that these people should include <Ontology> tags is all of
their documents (see daml.org's list of data sets for a number of
examples of DAML documents without these tags)? Or are you suggesting
that we should call these ontologies too? I think the later would really
confuse users to call every document an ontology, but only some
ontologies are <Ontology> ontologies. In any case, all of our documents
need to be a lot more clear about terminology (e.g., which definition of
ontology does our WG use) and about how people should use ontologies to
describe real content.

Jeff

pat hayes wrote:
> 
> >pat hayes wrote:
> >>
> >>  >Here's some initial comments on the Semantics document dated Nov. 3:
> >>  >
> >>  >1) Sect. 2.2. The syntax needs the ability to represent documents that
> >>  >consist soley of facts (that is, something other than ontologies).
> >>
> >>  ? Can you explain what you mean by "other than ontologies" ?Do you
> >>  mean, not in OWL?
> >>
> >
> >Part of this depends on what you consider OWL. From your response, I
> >assume that you think of OWL as just a language for defining ontologies,
> >and that you must use it with RDF in order to describe data
> 
> No. I fail to see the distinction you are drawing between 'ontology'
> and 'data'. I don't know what you mean by this, or what importance it
> has. One can have valid OWL documents which consist of nothing but
> ground RDF facts. So?
> 
> >(e.g., a
> >product catalog, a univeristy's course offerings, etc.). I tend to think
> >of OWL as an extension to RDF, so this data is still part of OWL, it
> >just has the standard RDF syntax.
> >
> >In any case, our model theory must talk about data to the same extent
> >that it talks about ontologies.
> 
> It does. It always has done. What is the problem?
> 
> Pat
> 
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Received on Thursday, 7 November 2002 14:21:31 GMT

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