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Re: An XML ``presentation'' syntax for OWL

From: Jeff Heflin <heflin@cse.lehigh.edu>
Date: Fri, 31 May 2002 17:03:36 -0400
Message-ID: <3CF7E528.192C3E1C@cse.lehigh.edu>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: www-webont-wg@w3.org

"Peter F. Patel-Schneider" wrote:
> 
> From: Jeff Heflin <heflin@cse.lehigh.edu>
> Subject: Re: An XML ``presentation'' syntax for OWL
> Date: Wed, 29 May 2002 16:04:57 -0400
> 

<snip>

> >  <owl:restriction>                              <!-- Unnecessary
> > STRIPING,SCHEMA -->
> >   <owl:IndividualRestriction owl:property="child"
> >                          owl:atmost="1">        <!-- Good -->
> >    <owl:range>                                  <!-- range="Person" ?
> > -->
> >     <owl:Class owl:ID="Person" />               <!-- ""
> > SCHEMA -->
> >    </owl:range>                                 <!-- "" -->
> >   </owl:IndividualRestriction>                  <!-- OK -->
> >  </owl:restriction>                             <!-- Unnecessary
> > STRIPING,SCHEMA -->
> >
> > J: Is the above restriction a qualified number restriction? If so, your
> > latest feature synopsis says these were supposed to be removed due to a
> > WG decision.
> 
> No, this is not a qualified number restriction.  This is, instead, a
> combination restriction, which consists of a maximum number restriction as
> well as an independent range restriction.  (That is, here there can be at
> most on child, and all of them have to belong to Person.)

Well then I'd say this syntax can lead to user confusion. Since the
class is a content element of the restriction that has the cardinality
attribute, it seems reasonable to expect that the cardinality applies to
the class, and not that they are independent. To make it clear that they
are independent, you should have separate elements for them.
 
<snip>

> > J: One final thing, as your comments suggest, the striping really does
> > seem to get in the way of clean syntax.
> 
> The striping is really only a separate problem in the individual syntax.
> In class and property axioms XML Schema has limitations that make the
> syntax pretty much striped.

Really, could you explain this? I imagine I could write an XML DTD that
didn't require the striping. Why should XML Schema be more restrictive?


> > Jeff
> 
> peter
Received on Friday, 31 May 2002 17:04:21 GMT

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