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Re: LANG: syntactic version for imports (and other things)

From: Jeff Heflin <heflin@cse.lehigh.edu>
Date: Tue, 17 Sep 2002 13:44:02 -0400
Message-ID: <3D8769E2.83F0FD8B@cse.lehigh.edu>
To: "Smith, Michael K" <michael.smith@eds.com>
CC: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, www-webont-wg@w3.org

Hi Mike,

Your message spawned a somewhat radical idea. What if we embed the RDF
stuff in the OWL stuff? That is, we have a set of OWL tags that allow us
to say any OWL things anyway we want, and then we have an RDF portion of
the ontology. For example:

<owl:ontology xmlns=...>
<!-- Here's some XML "extralogical" stuff -->
<owl:backCompatWith resource="uri1" />
<owl:imports resource="uri2" />

<!-- Here comes the RDF class and property definitions --!>
<rdf:RDF>
   <owl:Class ...>
   ...
   <owl:Property ...>
    ...
</rdf:RDF>

</owl:ontology>

Now, the "extralogical" stuff is clearly outside of the purview of RDF
but RDF processors can still read the class and property descriptions
without hiccuping.

Jeff

"Smith, Michael K" wrote:
> 
> Peter,
> 
> >> Define owl:ontology to be an extended alias for rdf:rdf.  An OWL
> >> ontology would then look like
> >>
> >> <owl:ontology about=""
> >>               xmlns="#"
> >>               xmlns:rdf=...>
> >>  <owl:imports about="" rdf:resource="uri1">
> >>  ...
> >> </owl:ontology>
> >
> > [snip] However, then the imports stuff is a node element, and
> > not a property element.
> 
> Good point.  So let each import be an instance of the import class,
> with an imports relation to the uri.
> 
> <owl:ontology about="" ... >
>  <owl:import imports="uri1"/>
>  <owl:import imports="uri2"/>
>  ..
> </rdf:RDF>
> 
> If the primary utility of this statement is to pull in another
> ontology, we really don't care too much what this looks like in RDF,
> as long as it isn't complete nonsense and doesn't generate any bogus
> entailments.  We want OWL to effectively discard it.  It should work
> like a comment.  It is astonishing that it is so hard to define such a
> thing.  Don't get me started.
> 
> - Mike
> 
> -----Original Message-----
> From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com]
> Sent: Tuesday, September 17, 2002 10:29 AM
> To: Smith, Michael K
> Cc: www-webont-wg@w3.org
> Subject: Re: LANG: syntactic version for imports (and other things)
> 
> From: "Smith, Michael K" <michael.smith@eds.com>
> Subject: RE: LANG: syntactic version for imports (and other things)
> Date: Tue, 17 Sep 2002 10:08:12 -0500
> 
> > Well now that I have slept on my flame I have a concrete suggestion.
> >
> > MOTIVIATION
> >
> > There is a desire to
> >
> > 1. indicate that a set of class, property, and individual definitions
> > are part of an ontology using a natural scoping mechanism (even if
> > this is an extra-logical relationship),
> >
> > 2. provide a strictly syntactic explanation for imports (at least I
> > would like to see this), and
> >
> > 3. maintain the basic RDF striping XML syntax.
> >
> > Note that RDF tools are going to need to make some slight changes
> > already (for example to support parsetype collection).
> >
> > SUGGESTION
> >
> > Define owl:ontology to be an extended alias for rdf:rdf.  An OWL
> > ontology would then look like
> >
> > <owl:ontology about=""
> >               xmlns="#"
> >               xmlns:rdf=...>
> >  <owl:imports about="" rdf:resource="uri1">
> >  ...
> > </owl:ontology>
> 
> Good idea, particularly having OWL documents be RDF documents (or whatever
> the the top-level of RDF is called) but owl:ontology elements instead of
> rdf:RDF elements.  However, then the imports stuff is a node element, and
> not a property element.
> 
> > The 'about' attribute (ignored by RDF) defines a name for the
> > ontology.  The standard cliche defaults to the document URL,
> > but we could insert an explicit URI if desired.
> > I believe that well engineered ontologies will want to be associated
> > with a URN so that they are not tied to a physical location.
> 
> > I'm still not clear on whether we want to introduce an ontology
> > resource into the RDF triple world.  We could always leave off the
> > 'about=""' in the imports clause and get an existential triple like
> >
> > _g001 owl:imports uri1
> 
> A node element doesn't work this way.
> 
> > In either case, the expansion of the imports could then be made to
> > work in a natural way, but would require supporting multiple
> > owl:ontology expressions in one file.  E.g.
> 
> Expansion of imports doesn't have to result in a ``file''.  It can be
> handled in a special way in the syntax.
> 
> > <owl:ontology about=""
> >               xmlns="#"
> >               xmlns:rdf=...>
> >  ...
> > </owl:ontology>
> >
> > <owl:ontology xml:Base="uri1"
> >               xmlns:ns11="uri11" ...
> >               xmlns:ns1i="uri1i"
> >               about="">
> >  ...
> > </owl:ontology>
> >
> > - Mike
Received on Tuesday, 17 September 2002 13:44:05 GMT

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