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OWL Questions

From: Ben Juby <bpj00r@ecs.soton.ac.uk>
Date: Thu, 18 Mar 2004 14:07:17 +0000 (GMT)
To: www-rdf-interest@w3.org
Message-ID: <Pine.LNX.4.44.0403181406130.5926-100000@login.ecs.soton.ac.uk>

Hi,

I'm currently in the process of writing an OWL ontology that imports and 
extends a couple existing ontologies and I have encountered a couple of 
issues I'm unsure about and would be grateful if somebody could please 
help clarify a couple things for me.

My first question is how owl:allValuesFrom restrictions affect 
owl:TransitiveProperties: (sorry, the explanation goes on for a bit...) 

My ontology (lets say myont) extends a location ontology. The location 
ontology defines a number of classes such as Room, Floor (e.g. the second
floor etc.), and Building, which are all rdf:subClassOf another class called
Abstract-Space.

Abstract-Space has a property called 'is-part-of', so it is possible to 
say things like "a Room is-part-of a Floor" and "a Floor is-part-of a 
Building" etc. The location ontology does not howevever define 
'is-part-of' as an owl:TransitiveProperty, so in myont I define that 
'is-part-of' is transitive as I wish to use the entailments this will 
provide.

The problem is that in the location ontology, the definition of the 
Room class has an owl:AllValuesFrom restriction on 'is-part-of' 
restricting it to members of the Floor class, and similarly the Floor 
class has 'is-part-of' restricted to instances of the Buliding class.       

My question is, given the AllValuesFrom restrictions on 'is-part-of', is 
it still possible (and correct) to define it as transitive, as that would 
then lead to entailments like "a Room is-part-of a Building", which would 
violate the AllValuesFrom restrictions.

My second question is about namespaces and owl:imports:

myont imports the location ontology (location). Does that also import 
everyting from the location ontology into the myont namespace? E.g. could 
I now refer to 'location:Building' also as 'myont:Building'? (assuming 
that Location is the base namespace for the location ontology and myont 
is the base namespace for the myont ontology). 

My final question is: 

Leaving any problems with the AllValuesfrom restrictions aside, is the 
following code extract the correct way to declare in myont that
location:is-part-of is an owl:TransitiveProperty? (i.e. is rdf:Description
the correct thing to use?)  
   
  <rdf:Description rdf:about="&location;is-part-of">  
    <rdf:type rdf:resource="&owl;TransitiveProperty" />
  </rdf:Description>
      
Many thanks,

Ben Juby 

Intelligence, Agents, Multimedia Group
School of Electronics and Computer Science
University of Southampton
Southampton
SO17 1BJ
UK
Received on Thursday, 18 March 2004 09:10:37 UTC

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