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Re: Lang: owl:ontolgy

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 13 Sep 2002 13:43:01 -0400 (EDT)
Message-Id: <20020913.134301.01447211.pfps@research.bell-labs.com>
To: hendler@cs.umd.edu
Cc: michael.smith@eds.com, www-webont-wg@w3.org

From: Jim Hendler <hendler@cs.umd.edu>
Subject: Lang: owl:ontolgy (was RE: LANG: syntactic version for imports (and other things))
Date: Thu, 12 Sep 2002 15:39:06 -0400

[...]

> The idea is that we can simply extend the owl:ontology to define its 
> classes in a manner similar to how RSS defines a channel (for those 
> who know that) -- that is, we create an owl:ontology statement that 
> includes a pointer to the set of URIs which it includes (could be 
> just class definitions, could be more).  This would look something 
> like this:
> 
> <rdf:RDF  {namespaces} >
> 
> <owl:class rdf:ID="foo">
>    <restriction ... (etc) />
> </owl:class>
> 
> <owl:class rdf:ID="bar">
>    <restriction ... (etc) />
> </owl:class>
> 
> <owl:class rdf:ID="baz">
>    <restriction ... (etc) />
> </owl:class>
> 
> <owl:Ontology rdf:ID="OntologyName">
>   <owl:ontologyDefines rdf:parsetype="collection">
>      <owl:ontologyClass :foo />
>      <owl:ontologyClass :bar />
>      <owl:ontologyClass :baz />
>   </owl:ontologyDefines>
>    <dc:creator rdf:ID="me" />
>       {other metadata}
> </owl:Ontology>
> 
> </rdf:RDF>

What happens if a class is ``claimed'' by no ontology?  What happens if it
is claimed by more than one ontology?

What is the meaning of this?  What aspects of :foo, etc., are part of this
ontology?

> The beauty of this is that I could now handle imports in various ways 
> - I could import an entire ontology with an imports statement within 
> this
> 
> <owl:Ontology ...>
>    <owl:imports URI2 />
> 
> and extend it
> 
>    <owl:Defines ...>
>      <owl:ontologyClass :notInURI2>
>    </owl:defines>
> ...
> <owl:Ontology>

How would this be different from any other mechanism for ontologies?

> I could include classes from other ontologies (Without importing the 
> whole thing) by simply including them in my owl:ontologyDefines 
> collection
>    <owl:OntologyClass cyc:dog>

What is the impact of this?  That cyc:dog is a resource in this ontology?
That the axioms about cyc:dog (from where?) are to be included in this
ontology?

I don't see any advantage here either.

> and I get for free some new properties that seem quite desirable - in 
> particular, I could create multiple ontologies in a document by 
> including pointers to different subsets

Is this an advantage?  It seems natural to have a 1-1 correspondence
between documents and ontologies.

> <owl:ontology rdf:ID="Pets">
>    ...
>    <owl:ontologyDefines>
>        ... dog
>        ... cat
>    </owl:ontologyDefines></owl:ontology>
> 
> <owl:ontology rdf:ID="Felines">
>    ...
>    <owl:ontologyDefines>
>        ... lion
>            cat
>            tiger
>    </owl:ontologyDefines></owl:ontology>

Again, which aspects of cat are part of Pets and which are part of Felines?  

> I think that version info could also be handled in here, although 
> still working on details.
> 
> I also think this works syntactically whether we put ontologies into 
> the domain of discourse or not -- I personally wouldn't prefer to, 
> but could go either way.
> 
>   -JH

peter
Received on Friday, 13 September 2002 13:43:15 GMT

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