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owl:Ontology issue

From: Evan Wallace <ewallace@cme.nist.gov>
Date: Fri, 8 Nov 2002 18:01:28 -0500 (EST)
Message-Id: <200211082301.SAA04593@clue.msid.cme.nist.gov>
To: www-webont-wg@w3.org


It looks to me like we have an issue regarding what the 
Ontology construct is intended to mean.  I have written up
an issue submission.  In it I have tried to pull out what our
working drafts have to say about the issue and the positions 
that have been espoused in recent emails.

-Evan


*****


TITLE: Intended usage of the Ontology header tag 
		     or 
	   What is an "OWL Ontology?"

DESCRIPTION: 

There is disagreement on the intended usage of owl:Ontology.  The OWL
reference document [1] describes a language element owl:Ontology as a
header to contain metadata such as version info, comments, and imports
for the owl document which contains it.  Guide describes this
construct as "an assertion that what follows is an OWL ontology."  So
the question really seems to be, What is an "OWL Ontology?"

The OWL Reference includes [2] Appendix C. which contains

<!-- A class for ontologies themselves... -->

<rdfs:Class rdf:ID="Ontology">
  <rdfs:label>Ontology</rdfs:label>
  <rdfs:comment>
    An Ontology is a document that describes
    a vocabulary of terms for communication between
    (human and) automated agents.
  </rdfs:comment>
</rdfs:Class>


Positions:

JH in [3]:

(OWL) Ontology documents are those that define classes and properties.
Instance documents are defined by using RDF to produce instances (or 
individuals) that are members of those classes with those properties.

PHayes in [4]:

I have no problem with that, but I have always understood this to 
simply be an XML marker for the presence of OWL syntax in the RDF 
graph. Why do we need to say anything more than that? "owl:ontology" 
isn't in the graph, right? So its not in the namespace, and it has no 
semantics. If "owl:ontology" is in the OWL namespace, then we ought 
to say what an RDF triple which includes that name means.

[short paraphrase : An OWL Ontology is an rdf document which contains
OWL syntax.]

[note regarding Ontology in the OWL namespace: Guide's example [5]
refers to [2] in identifying the owl namespace.  The excerpt from [2]
above defines a named class:Ontology, putting it in the owl
namespace.]

RAISED BY: E. Wallace, email of 8 Nov 2002

REFERENCES:
[1] http://www.w3.org/TR/2002/WD-owl-ref-20020729/#Ontology-def
[2] http://www.w3.org/2002/07/owl
[3] http://lists.w3.org/Archives/Public/www-webont-wg/2002Nov/0098.html
[4] http://lists.w3.org/Archives/Public/www-webont-wg/2002Nov/0113.html
[5] http://www.w3.org/TR/owl-guide/#Namespaces
Received on Friday, 8 November 2002 18:01:37 GMT

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