- From: Matt Halstead <matt.halstead@auckland.ac.nz>
- Date: Fri, 23 May 2003 12:40:18 +1200
- To: www-rdf-logic@w3c.org
from http://www.daml.org/2001/03/daml+oil-walkthru#restrictions
-----snip------
The next few lines describe a class-specific range restriction. In
particular, the parent of a Person is also a Person.
<rdfs:subClassOf>
<daml:Restriction>
<daml:onProperty rdf:resource="#hasParent"/>
<daml:toClass rdf:resource="#Person"/>
</daml:Restriction>
</rdfs:subClassOf>
What happens here is that the Restriction defines an anonymous class,
namely the class of all things that satisfy the restriction. In this
case: the class of all things whose parent is a Person. We then demand
that the class Person is a subClassOf this (anonymous) class. In other
words: we demand that every Person must satisfy this Restriction, which
in this case amounts to demanding that Persons have only Persons as
their parents.
-----snip------
This could suggest the default cardinality is 1 in DAML+OIL, perhaps it
could be made clearer by saying that if a person does have this property
then it demands....
Hmm, perhaps it is a minimum of 1, come to think of it, I can't find
where such a notion is explicitly stated.
Received on Thursday, 22 May 2003 20:40:28 UTC