RE: rdf:Property used as rdf:object in a triple

Hi Paul,
 
Thanks for your response! (and thanks as well to Chris and Frank).
 
Let me explain this with a simple example:

*	

	John isInvolvedWith Jane
*	

	Jane's father Pete givesApprovalTo that relationship

This means that the isInvolvedWith relationship is the rdf:object of the
predicate 'givesApprovalTo'.
 
We then also want to represent the owl:Restriction that Fathers approve such
relationships of their daughters (granted, it's a bit old-fashioned, but
it's just an example).
 
This example is not rare. Another one is:

*	

	Nozzle N1 isWeldedTo Vessel V1
*	

	that welded connection isInspectedBy John

I guess that I should start using reification, but quite honestly I am too
dumb to understand the text in [1]
[1] HYPERLINK
"http://www.w3.org/TR/rdf-mt/#Reif"http://www.w3.org/TR/rdf-mt/#Reif
 
Is reification at all possible in an OWL environment? It seems not to be the
case.
 
Mind you, we define "templates" with Restrictions in OWL that will be used
to validate the zillions of instances of those templates in RDF. So for
example we define, using 15926 model lingo, a template for DirectConnection
of two PossibleIndividuals, and make sure, using owl:Restrictions, that any
instance of that template has an instance of PossibleIndividual at both
sides. These templates can be specialized by onProperty restrictions to, for
example, a template for welded connections that can only be between
instances of PossibleIndividual that can be welded at all.
 
I hope I haven't made this too complex :-)
 
Regards,
Hans
 
____________________
OntoConsult
Hans Teijgeler
ISO 15926 specialist
Netherlands
+31-72-509 2005
HYPERLINK "http://www.infowebml.ws/"www.InfowebML.ws 
HYPERLINK "mailto:hans.teijgeler@quicknet.nl"hans.teijgeler@quicknet.nl
 

   _____  

From: Paul Gearon [mailto:gearon@ieee.org] 
Sent: Saturday, November 04, 2006 23:56
To: Hans Teijgeler
Cc: SW-forum
Subject: Re: rdf:Property used as rdf:object in a triple



On Nov 4, 2006, at 6:25 AM, Hans Teijgeler wrote:


Folks,
 
rdf:Property is a subClassOf rdfs:Resource, so syntactically a property
could be the rdf:object of a triple.
 
My question is, whether or not there is something against doing that from a
semantics/reasoning point of view.
 
Can anybody shed some light on this?


There's certainly no rule against it.  Reification requires it.  So does
rdfs:subPropertyOf.

As for semantics... you can get away with a lot in RDF.  But if you want to
keep things as valid OWL-Lite or OWL-DL then you have to be more careful, as
properties are treated a little differently to other resources.  Properties
only start getting back the "privileges" of other types of resources (like
classes) when you get up to OWL-Full.

Paul


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