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RE: TODO++: daml-ont TallThing

From: Hart, Lewis <lhart@grci.com>
Date: Fri, 3 Nov 2000 14:27:30 -0500
Message-ID: <09A65DF294F8D311AAB000105A02DBAF01BE9312@thumper.va.grci.com>
To: Ian Horrocks <horrocks@cs.man.ac.uk>, "McBride, Brian" <bwm@hplb.hpl.hp.com>
Cc: www-rdf-logic@w3.org
>From: Ian Horrocks [mailto:horrocks@cs.man.ac.uk]
>Sent: Friday, November 03, 2000 4:46 AM
>To: McBride, Brian
>Cc: www-rdf-logic@w3.org
>Subject: RE: TODO++: daml-ont TallThing
>On November 1, McBride, Brian writes:
>> > > There are a couple of minor nits in the example ontology:
>> > > 
>> > > 1) Father is desribed as having range Man, but presumably
>> > >    inherits domain Animal from Parent.  Mother is similar.
>> A mother of a fox is not human.  I'd expect the domain and range
>> to match i.e. domain of mother is person if range is woman, or
>> range of mother is female animal if domain is animal.
>> A real nit - sorry.
>> Brian
>This is another example of a point I made in an earlier discussion on
>rdf-interest, namely that domain and range restrictions are very
>strong assertions, and that a value restriction on the domain class is
>usually more appropriate. 
>For example, when the domain and range of a property P are restricted
>to classes D and R respectively, the intended meaning often is (or
>should be) that IF (i,j) is an instance of P AND i is an instance of D
>THEN j must be an instance of R. ...

So, do this mean that once you have said, in ontology O1:

<Class ID="D">
      <onProperty resource="#P"/>

      <toClass resource="#R"/>


no one else could say, in ontology O2:

<Class ID="D">
      <onProperty resource="#P"/>

      <toClass resource="#R2"/>


For example, let D := Person, P := authorOf, R := Book, and R2 := Ontology 

It seems to be preferred to use restrictions at the most general level they
apply. In my example restricting authorOf to "AuthorableThings" which has
Book and Ontology as subclasses. I am not sure how this could be determined
a priori in the web environment. But, the more general class could be
inferred as a requirement for working simultaneously with statements
expressed in O1 and O2.

- Lewis
Lewis L Hart 
GRC International                     lhart@grci.com
1900 Gallows Rd.                  Voice (703)506-5938
Vienna, Va 22182                    Fax (703)556-4261
Received on Friday, 3 November 2000 14:31:24 UTC

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