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[closed] Re: OWL abstract syntax: -lite, -dl restrictions

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 14 May 2003 10:49:15 -0400
Message-Id: <p05200f45bae8079c3762@[129.2.176.174]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
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

oops, forgot the [closed] tag - added here - one of the joys of using 
automated tools is that they are so forgiving :->

>
>
>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

-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
http://www.cs.umd.edu/users/hendler
Received on Wednesday, 14 May 2003 10:49:25 GMT

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