- 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
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:hasSlotConstraint>
<oil:has-value>
<oil:hasProperty rdf:resource="#P"/>
<oil:hasClass rdf:resource="#R"/>
<oil:has-value/>
<oil:hasSlotConstraint/>
<rdfs:class/>
or in DAML-O
<Class ID="D">
<restrictedBy>
<Restriction>
<onProperty resource="#P"/>
<toClass resource="#R"/>
</Restriction>
</restrictedBy>
</Class>
Received on Friday, 3 November 2000 05:23:36 UTC