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Re: OWL abstract syntax: -lite, -dl restrictions

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 14 May 2003 10:36:49 -0400 (EDT)
Message-Id: <20030514.103649.59794487.pfps@research.bell-labs.com>
To: Graham Klyne <gk@ninebynine.org>
Cc: public-webont-comments@w3.org

In my previous message I forgot to either close the thread or ask if you
needed any more information.

I'm going to do both here.  :-)

Please reply if there is anything more that needs to be done on this
thread.

Peter F. Patel-Schneider
Bell Labs Research
Lucent Technologies


From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Subject: Re: OWL abstract syntax: -lite, -dl restrictions
Date: Fri, 09 May 2003 15:00:27 -0400 (EDT)

> From: Graham Klyne <gk@ninebynine.org>
> Subject: OWL abstract syntax: -lite, -dl restrictions
> Date: Tue, 06 May 2003 17:29:37 +0100
> 
> > With reference to:
> >    http://www.w3.org/TR/owl-semantics/syntax.html#2.3.1.2
> > and
> >    http://www.w3.org/TR/owl-semantics/syntax.html#2.3.2.3
> > 
> > I see that for OWL-lite:
> > [[
> > restriction ::= 'restriction(' datavaluedPropertyID 
> > dataRestrictionComponent ')'
> >              | 'restriction(' individualvaluedPropertyID 
> > objectRestrictionComponent ')'
> > ]]
> > 
> > But for OWL-DL:
> > [[
> > restriction ::= 'restriction(' datavaluedPropertyID 
> > dataRestrictionComponent { dataRestrictionComponent } ')'
> >              | 'restriction(' individualvaluedPropertyID 
> > objectRestrictionComponent { objectRestrictionComponent } ')'
> > ]]
> > 
> > Is it intended that a restriction may have only one component in OWL-lite?
> 
> Yes, this is intended.
> 
> > This restriction (sic) seems rather pointless, as I think an axiom naming a 
> > class can be repeated with multiple single-component restrictions to 
> > achieve the same effect.
> 
> The more-complex construction in OWL DL is strictly convenience, as there
> it can always be replaced by an intersection.  However, in OWL Lite, this
> replacement is not always (easily) possible, leading to difficulties as to
> just what can be said in OWL Lite.
> 
> > Also, I note that OWL-lite restrictions do not include the single-value 
> > form of restriction "Value( _ )".  Is this intended?
> 
> Yes, this is as intended.  The Value(_) construction augments the
> expressive power of the language and was not put in OWL Lite for this
> reason.   
> 
> > (I see no purpose in raising a formal issue for this.)
> > 
> > #g
> 
> Peter F. Patel-Schneider
> Bell Labs Research
> Lucent Technologies
Received on Wednesday, 14 May 2003 10:36:59 GMT

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