RE: Restriction

Thanks Peter, 

It is probably a bad example, but I was simply trying to state a general
axiom:

	exists callThemselves "Human" implies HomoSapien.

Which is exactly what you said in your PS

> > It does not violate the definition of owl restriction, as it has
exactly
> > one onProperty, and exactly one value constraint.
> ...
> means.  However, it is not legal OWL DL, because there is no way to
have
> extras properties on restrictions in OWL DL.
>
Hmm... ok, I can accept that. Just so that I could reference it in my
code, I would be grateful if you could kindly point me to the location
where this is explicitly mentioned. I have been trying to locate this in
the specification docs (last call), I am afraid I cannot find any
supporting evidence in the doc that indicates it is invalid OWL-DL.

According to the reference doc, 

	- a restriction is a special kind of class description, and
	- AXIOM SCHEMA: class description rfs:subClassOf class
description

And the AS&S seems to support these two statements too.

Given that I cannot use this RDF form to say it in OWL-DL, then I'd have
to use:

<owl:Class>
  <owl:equivalentClass>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#callThemselves" />
      <owl:hasValue   rdf:datatype="&xsd;string">Human</owl:hasValue>
    </owl:Restriction>
  </owl:equivalentClass>
  <rdfs:subClassOf rdf:resource="#HomoSapien"/>
</owl:Class>

or 

<owl:Class>
  <owl:intersectionOf> <!-- or unionOf... shouldn't make any difference
-->
    <owl:Restriction>
      <owl:onProperty rdf:resource="#callThemselves" />
      <owl:hasValue   rdf:datatype="&xsd;string">Human</owl:hasValue>
    </owl:Restriction>
  </owl:intersectionOf>
  <rdfs:subClassOf rdf:resource="#HomoSapien"/>
</owl:Class>

All three forms should result in the same semantics right? Although the
exact number of axioms and their structure may be slightly different.

Many thanks, 

Gary

> -----Original Message-----
> From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com]
> Sent: 06 August 2003 18:02
> To: Gary Ng
> Cc: www-rdf-logic@w3.org
> Subject: Re: Restriction
> 
> From: "Gary Ng" <Gary.Ng@networkinference.com>
> Subject: owl:Restriction
> Date: Tue, 5 Aug 2003 12:04:48 +0100
> 
> >
> >
> > Hi all,
> >
> > I am confused as to whether the following piece of OWL is valid:
> >
> > <owl:Restriction>
> >   <owl:onProperty rdf:resource="#callThemselves" />
> >   <owl:hasValue   rdf:datatype="&xsd;string">Human</owl:hasValue>
> >   <rdfs:subClassOf rdf:resource="#HomoSapien"/>
> > </owl:Restriction>
> >
> > It does not violate the definition of owl restriction, as it has
exactly
> > one onProperty, and exactly one value constraint.
> >
> > I believe this is valid (albeit unconventional) as owl:Restriction
is a
> > "subclass" of owl:Class. The normative RDF Schema for owl seems to
> > suggest that anything that can appear within owl:Class can certainly
> > appear in owl:Restriction in the RDF XML format. (e.g. the
rdfs:domain
> > for intersectionOf is a Class).
> >
> > Please yell if I am totally wrong. If it is invalid, we need to make
> > sure our tools do not export this form.
> >
> > Cheers,
> >
> > Gary
> >
> >
> > Gary Ng, PhD 	     gary.ng@networkinference.com
> > Senior Software Engineer
> > Network Inference (Holdings) Ltd
> > Tel: +44 (0) 20 7616 0717 Fax: +44 (0) 20 7616 0701
> 
> 
> This is legal OWL Full, and might even mean what you think that it
> means.  However, it is not legal OWL DL, because there is no way to
have
> extras properties on restrictions in OWL DL.
> 
> peter
> 
> PS:  The meaning of this is that if something has a callThemselves
> property value of "Human" then it is a HomoSapien.

Received on Thursday, 7 August 2003 14:04:55 UTC