RE: representing non-state relationships in OWL

Hi Chris,
I agree that in RDF one can't qualify properties attached to resources
(except for identity, ie. rdf:node) without resorting to reficiations
perhaps. At the same time, it seems easiest to describe the meeting, rather
than to describe Peter, as in:

<Meeting rdf:ID='Meeting01'>
  <meetingHost rdf:resource='#Peter'/>
  <meetingTimeStart rdf:resource='#ThreePM'/>
  <meetingTimeEnd rdf:resource='#FivePM'/>
  <meetingLocation rdf:resource='#Rm305'/>
</Meeting>

But you want to identify Peter as a host and to describe the meeting that
Peter is hosting, maybe you could associate those attributes with a
description of the role that Peter fulfills:

<HumanBeing rdf:ID='Peter'>
   <has>
     <HostRole>
        <hostEvent rdf:resource='#Meeting01'/>
        <hostTimeStart rdf:resource='#ThreePM'/>
        <hostTimeEnd rdf:resource='#FivePM'/>
        <hostLocation rdf:resource='#Rm305'/>
     </HostRole>
   </has>
</HumanBeing>

The 'has' property is part of the ontology that I'm working on at
Legal-RDF.org (see the ontology's WIKI here).
Thanks,
John




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  From: C Haley [mailto:cands589@yahoo.co.uk]
  Sent: Monday, September 11, 2006 20:23
  To: public-owl-dev@w3.org
  Subject:


  Hi

  I’ve been reading through the various OWL documents and from what I’ve
seen it appears that OWL is very good at representing state information,
either of classes or individuals, but does not seem to allow for
representing non-state relationships.

  For example I can use OWL to represent the concept ‘man’ as a class,
represent Peter as an instance of that class, and I can define a property
stateOfHealth, and the concept ill, and create a triple to say
stateOfHealth(Peter, ill). This is representing a fact which defines the
state of an instance.

  But suppose I want to represent the fact that Peter hosted a meeting in
the office yesterday.

  Even if I created an artificial property ‘toHost’ and a blank node as an
instance of the concept ‘meeting’, there is no way to attach the time and
location to the property.

  Also I would want this property to derive from a URI representing the
concept of ‘hosting a meeting’, but the OWL syntax seems to require
properties to derive from other properties, not from a generic URI. So
clearly this is not the correct way to represent an action.

  Can anyone tell me if there are any recommendations or documents
describing the preferred solution to this problem? Alternatively is this an
area where the existing OWL syntax/vocabulary is likely to be extended - is
anyone actively working on this issue at present? Are there any draft
recommendations in circulation?

  Many thanks for any comments anyone can give.

  Chris