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Re: WOWG: first language proposal (fwd)

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Fri, 5 Apr 2002 23:14:02 +0100
Message-ID: <15534.8618.86483.564196@oaklands.demon.co.uk>
To: www-webont-wg@w3.org
------- start of forwarded message -------
From: Ian Horrocks <horrocks@cs.man.ac.uk>
To: "Jonathan Borden" <jonathan@openhealth.org>
Date: Fri, 5 Apr 2002 20:47:31 +0100
Subject: Re: WOWG: first language proposal
Reply-To: Ian Horrocks <horrocks@cs.man.ac.uk>

On April 5, Jonathan Borden writes:
> Jeff Heflin wrote:
> 
> > 
> > Yes, that is basically what I mean. In an earlier message [1], I gave
> > some examples of what an XML syntax for WebOnt might look like. One
> > example from that message was:
> > 
> > <!-- This says that a trio has three members, all of whom are musicians.
> > -->
> >   <owl:class ID="Trio">
> >      <owl:hasProperty ref="#hasMember">
> >         <owl:cardinality value="3" />
> >         <owl:allvalues>
> >            <owl:class ref="#Musician" />
> >         </owl:allvalues>
> >      </owl:hasProperty>
> >   </owl:class>
> 
> but in something RDF compatible:
> 
> <Class rdf:ID="Trio">
>         <subClassOf>
>                 <Restriction>
>                         <onProperty rdf:resource="#hasMember"/>
>                         <cardinality>3</cardinality>
>                         <rdf:range rdf:resource="#Musician"/>
>                 </Restriction>
>         </subClassOf>
> </Class>
> 
> which, gosh, isn't all that different, is it?

But some problems that now arise are:

1. Various parts of the syntactic structure are given unwanted logical
significance by RDF.

2. Unlike in the XML form, it is difficult/impossible to restrict the
syntax to just this form, so we have to be able to cope with things
like:

<Class rdf:ID="Trio">
        <subClassOf>
                <Restriction>
                        <onProperty rdf:resource="#hasMember"/>
                        <onProperty rdf:resource="#playsMusicBy"/>
                        <cardinality>3</cardinality>
                        <cardinality>5</cardinality>
                        <rdf:range rdf:resource="#Musician"/>
                        <rdf:range rdf:resource="#Composer"/>
                </Restriction>
        </subClassOf>
</Class>

It would be much more straightforward to have the parser reject this
as invalid (F)OWL - which we easily can do if we adopt Jeff's
solution.

Ian

> 
> Jonathan
> 
> 
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Received on Friday, 5 April 2002 17:16:27 GMT

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