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RE: TODO++: daml-ont TallThing

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Fri, 3 Nov 2000 09:45:31 +0000 (GMT)
To: "McBride, Brian" <bwm@hplb.hpl.hp.com>
Cc: www-rdf-logic@w3.org
Message-ID: <14850.33871.224950.603446@localhost.localdomain>
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. This can be expressed in OIL (and
DAML-O) using a value restriction on the class D.

e.g., in OIL:

<rdfs:class rdf:ID="D">
      <oil:hasProperty rdf:resource="#P"/>
      <oil:hasClass rdf:resource="#R"/>

or in DAML-O

<Class ID="D">
      <onProperty resource="#P"/>
      <toClass resource="#R"/>
Received on Friday, 3 November 2000 05:23:36 UTC

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