# Re: Proposed extensions to OWL?

From: Monika Solanki <monika@dmu.ac.uk>
Date: Sun, 15 Jun 2003 12:16:02 +0100
Message-ID: <3EEC5572.6050900@dmu.ac.uk>
To: "Roger L. Costello" <costello@mitre.org>

```Hi Roger,

I am facing a similar problem to yours. I have a class A, which has two
properties P1 and P2. I want to state that P2= P1-1. Incidentally I
could not find anyways in OWL to express this. Is there some cnstruct
in OWL to state this.

Thanks & Regards,

Monika

Roger L. Costello wrote:

>Hi Folks,
>
>mathematical relationships.  Robin Berjon responded with a very
>interesting idea.  I would like to get your thoughts on it, and see if
>collectively we can come up with something cool.
>
>First I will show you a slightly modified version of Robin's proposal,
>then I will show Robin's original proposal.
>
>Robin's Idea Slightly Modified
>
>The idea is to extend OWL and base the solution on xPath.
>
>Suppose that I would like to state that these two properties are
>equivalent via a conversion factor:
>
>     length-in, length-cm
>
>i.e., length in inches, and length in centimeters
>
>The conversion factor is:
>
>    length-in = length-cm / 2.54
>    length-cm = length-in * 2.54
>
>With today's OWL here is how you would define these properties:
>
>   <owl:DatatypeProperty rdf:ID="length-in">
>      <rdfs:range rdf:resourse="&xsd;decimal"/>
>   </owl:DatatypeProperty>
>
>   <owl:DatatypeProperty rdf:ID="length-cm">
>      <rdfs:range rdf:resourse="&xsd;decimal"/>
>   </owl:DatatypeProperty>
>
>The proposal is to extend OWL to allow you to assert that these two
>properties are equivalent by the above conversion factor.  Here's how it
>might look:
>
>   <owl:DatatypeProperty rdf:ID="length-in">
>      <owl:equivalentProperty rdf:resource="#length-cm"
>                        owl-x:conversionFactor="current() * 2.54"/>
>      <rdfs:range rdf:resourse="&xsd;decimal"/>
>   </owl:DatatypeProperty>
>
>   <owl:DatatypeProperty rdf:ID="length-cm">
>      <owl:equivalentProperty rdf:resource="#length-in"
>                        owl-x:conversionFactor="current() / 2.54"/>
>      <rdfs:range rdf:resourse="&xsd;decimal"/>
>   </owl:DatatypeProperty>
>
>where:
>   owl-x is an OWL eXtension namespace,
>   current() is the xPath function referring to the current node.
>
>Now let me show you Robin's idea:
>
>Robin's idea is also to base the solution on xPath. Here's what Robin
>said:
>
>"For instance:
>
><foo:PropertyEquivalence from='measure:inch'
>                          to='measure:cm'
>                          convert='\$in_1 * 2.54'/>
>
><foo:PropertyEquivalence from='measure:cm'
>                          to='measure:in'
>                          convert='\$in_1 div 2.54'/>
>
>would allow you to declare that the following are equivalent:
>
><geo:Distance>
>   <measure:inch>2</measure:inch>
></geo:Distance>
>
><geo:Distance>
>   <measure:cm>5.08</measure:cm>
></geo:Distance>
>
>You could allow for multiple inputs to your binding:
>
><foo:PropertyEquivalence
>                  from='size:width/measure:meter
>size:length/measure:meter'
>                  to='size:surface/measure:squareMeter'
>                  convert='\$in_1 * \$in_2'/>
>
>and perhaps equivalentize, depending on whether it makes sense in that
>context:
>
><flat:Bedroom>
>   <size:width><measure:meter>4</measure:meter></size:width>
>   <size:length><measure:meter>5</measure:meter></size:length>
></flat:Bedroom>
>
><flat:Bedroom>
>   <size:surface>
>     <measure:squareMeter>20</measure:squareMeter>
>   </size:surface>
></flat:Bedroom>
>
>so that given the first you could still query for flat:Bedrooms that
>are larger than 20sqm.
>
>You may need to throw in stuff from EXSLT Math if you want more than
>XPath provides."
>
>....
>
>Okay, those are the two ideas thus far.  What do you think?  Feel free
>so. The intent here is to brainstorm.  If these conversion rules are
>better stated using another technology (e.g., RuleML) please say so.
>/Roger
>

--
>**<>**<>**<>**<>**<>**<>**<>**<>**<>**<
Monika Solanki
De Montfort University
Software Technology Research Laboratory
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The Gateway.
Leicester LE1 9BH, UK

phone: +44 (0)116 250 6170 intern: 6170
email: monika@dmu.ac.uk <mailto:monika@dmu.ac.uk>
web: http://www.cse.dmu.ac.uk/~monika/
<http://www.cse.dmu.ac.uk/%7Emonika/>
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Received on Sunday, 15 June 2003 07:10:25 UTC

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