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Re: Lang: owl:ontolgy

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 13 Sep 2002 16:06:11 -0400 (EDT)
Message-Id: <20020913.160611.17067212.pfps@research.bell-labs.com>
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org

From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: Lang: owl:ontolgy
Date: Fri, 13 Sep 2002 14:33:34 -0400

> At 1:53 PM -0400 9/13/02, Peter F. Patel-Schneider wrote:
> >Here is a definition of ontologies that fits into the opposite end of the
> >spectrum from Jim's.
> >
> >Abstract Syntax View:
> >
> >An ontology is a syntactic construct that consists of a collection of
> >1/ facts and axioms;
> >2/ inclusions of other ontologies;
> >3/ extra-logical information about the ontology, such as creater, etc.
> >
> >RDF/XML View:
> >
> >An ontology is an RDF/XML document whose rdf:RDF element has the inclusions
> >and extra-logical information as attributes and the facts and axioms in its
> >elements.
> 
> how will you make it so the rdf:RDF element can
>    i. handle "structured" data - you make every extralogical thing be 
> a single element tag (i.e. not an RDF graph) because you cannot embed 
> a graph in the <rdf:RDF>

So far, I haven't seen an example that needs structured data in the
extra-logical portion.  

>   ii. The entities within the rdf:RDF cannot get their own URIs.  This 
> would strongly limit the linking of ontologies that many of us think 
> is important

Entities within the rdf:RDF get URIrefs and can easily be referenced by
these URIrefs.  

How would the linking of ontologies be limited?  The only linking right now
is from one ontology to another, via imports or the version stuff.  This
would be handled in the attributes above.

> >The meaning of an ontology is the combination of the meaning of the facts
> >and axioms in it plus the meaning of the ontologies included in it.
> >
> >
> >RDF View:
> >
> >An ontology is an RDF graph, containing the axioms and facts of the
> >ontology and the axioms and facts of all included ontologies and their
> >included ontologies, etc.
> >
> >That's it.
> 
> strangely enough, this is the solution I wanted to use, but the real 
> problem is that the rdf:RDF is too limited -- the idea of creating 
> the ontologyDefines tag is that you get exactly the same 
> functionality as the above without imposing these limits.

But you also get a whole pile of problems, some of which are described in
my previous message. 

>   -JH

peter
Received on Friday, 13 September 2002 16:06:20 GMT

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