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RE: Property Value Ranges

From: John McClure <jmcclure@hypergrove.com>
Date: Thu, 23 Aug 2007 11:39:20 -0700
To: "Ibach, Brandon L" <brandon.l.ibach@lmco.com>, "Owl Dev" <public-owl-dev@w3.org>
Message-ID: <MGEEIEEKKOMOLNHJAHMKCEMGEFAA.jmcclure@hypergrove.com>

Brandon,
I agree about using patterns in this instance... 
But my point is that it seems clearer to say:

<owl:DataRange rdf:about='#blny'>
    <owl11:onDataRange rdf:resource="&string;"/>
    <owl11:pattern rdf:datatype="&string;">[b-ln-y]</owl11:pattern>
</owl:DataRange>

<owl:Thing rdf:about="#a">
     <P rdf:resource='#blny'/>
</owl:Thing>

No rdf:typing is necessary and I think query & maintenance is alot easier.

Thanks,
John

>-----Original Message-----
>From: Ibach, Brandon L [mailto:brandon.l.ibach@lmco.com]
>Sent: Wednesday, August 22, 2007 7:18 PM
>To: John McClure; Owl Dev
>Subject: RE: Property Value Ranges
>
>
>John,
>	I'm not sure why you're uncomfortable with expressing
>constraints on an individual's property value using class-based
>mechanisms.  When you get right down to it, OWL only allows you to say
>what classes an individual belongs to and what values it *does* have for
>properties.  Anything more complicated than that, such as what values it
>*doesn't* have or which values it *could* have, are handled by defining
>class and property expressions, then relating the individual to these
>expressions with <rdf:type>.
>	A significant amount of the OWL language is, technically, syntax
>shortcuts that could be rewritten into other forms, all built on a
>handful of "primitive" constructs.  If your concern is simply that the
>new version of OWL won't have shortcuts for things you want to be able
>to model easily, you should certainly provide that feedback.  Of course,
>since you obviously have some experience in defining some syntax of your
>own, you might also consider using an extended version of OWL with
>special syntax that better meets your needs, so long as that syntax can
>be readily translated (using XSLT, for instance) into standard OWL that
>can then be fed to a reasoner or other processing tools.
>	All that said, I think your example could be expressed with
>something like the following, which (disclaimer!) I have not tested with
>any tools.  Hopefully, any errors on my part will be corrected in short
>order by those on the list more experienced than I. :)  Several
>variations on the means to define the allowed values are possible, if
>you don't care for the use of <owl11:pattern>, which I chose simply
>because it is the most compact (and because I'm a regexp junkie).
>
><owl:Thing rdf:about="#a">
>  <rdf:type>
>    <owl:Restriction>
>      <owl:onProperty rdf:resource="#P"/>
>      <owl:allValuesFrom>
>        <owl:DataRange>
>          <owl11:onDataRange
>rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
>          <owl11:pattern
>rdf:datatype="http://www.w3.org/2001/XMLSchema#string">[b-ln-y]</owl11:p
>attern>
>        </owl:DataRange>
>      </owl:allValuesFrom>
>    </owl:Restriction>
>  </rdf:type>
></owl:Thing>
>
>	If you find this somewhat verbose expression as part of the
>definition of an individual to be distasteful, I'd ask what it is about
>this one individual that motivates this restriction upon its value for
>this property.  My inclination is to say that this motivation is
>probably some aspect of this individual and that this aspect should be
>named and defined as a class in your ontology, in which case the
>declaration that this individual has that aspect would be a simple
>assignment of the individual as a member of the class and your property
>value restriction would be accomplished, neat and clean.
>
>-Brandon :)
>
>-----Original Message-----
>From: public-owl-dev-request@w3.org
>[mailto:public-owl-dev-request@w3.org] On Behalf Of John McClure
>Sent: Wednesday, August 22, 2007 2:57 PM
>To: Owl Dev
>Subject: Property Value Ranges
>
>
>I'm uncomfortable with the answer given for axioms about instance
>property
>values -- the answer used a <Restriction> element which is mechanism for
>class
>definitions. I'm concerned about the impact of this approach on
>user-queries of
>a knowledge-base and also on its maintenance by developers
>
>Let's consider for a moment that one wants to say an instance 'a' has a
>property
>'P' that has an exclusive range of values a-z, with the exception of
>value 'm'
>(and, being exclusive, of the endpoints). To me, that is a simple matter
>of
>
><owl:Thing rdf:about="#a">
>     <P verb='has'>
>          <Range>
>	<Minimum verb='has' rdf:value='a'/>
>	<Maximum verb='has' rdf:value='z'/>
>	<Value verb='hasNot' rdf:value='a'/>
>	<Value verb='hasNot' rdf:value='z'/>
>	<Value verb='hasNot' rdf:value='m'/>
>          </Range>
>     </P>
></owl:Thing>
>
>Would someone provide the OWL 1.1 equivalent coding (in XML)? I'm
>wondering if
>the values for P are spread across <rdf:type> and <P> element structures
>rather
>than packaged in a single element as shown above.
>
>Though feasible, using <rdf:type> elements to specify property values
>that an
>instance *does or doesn't have* seems strange from the perspective that
>it's
>hard to understand the actual significance of the extent of a class so
>obviously
>artificial.
>
>Thanks,
>John McClure
>
>
Received on Thursday, 23 August 2007 18:38:56 GMT

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