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Re: Properties in OWL

From: Guus Schreiber <schreiber@cs.vu.nl>
Date: Tue, 09 Dec 2003 18:35:44 +0000
Message-ID: <3FD61600.7050108@cs.vu.nl>
To: Yongchun Gao <yongchun.gao@mail.mcgill.ca>, Justo Ruiz <"mailto:justo.ruiz"@activiti.com>
Cc: www-rdf-interest <www-rdf-interest@w3.org>

Yongchun Gao wrote:
> Just follow your question: I have the same feeling.
> For example: suppose there is a property HasYield (integer), but what 
> about the unit this property is using,(Kg, g, etc.)? It is the quesion 
> of property about property.

Properties of properties are allowed in OWL Full.

In OWL DL classes and properties are disjoint, so you cannot express the 
notion of a UML association class directly. A well-known workaround is 
to define  an intermediate class, e.g. in the case of your problem a 
"Quantity" class with a value and a unit property. See the measurement 
example in Sec. 5.1 in OWL Reference [1].

Hope this helps,

[1] http://www.w3.org/TR/owl-ref/

> Could OWL figure out this situation?
> Thanks in advance!
> ----- Original Message -----
> From: Justo Ruiz <mailto:justo.ruiz@activiti.com>
> To: www-rdf-logic@w3.org <mailto:www-rdf-logic@w3.org>
> Sent: Friday, December 05, 2003 1:05 PM
> Subject: Properties in OWL
> All,
> I've been following OWL language evolution for a while and ever
> since I learnt about it, I had a question on my mind which I still
> haven't found a solution or explanation:  Why Properties cannot have
> properties?  That is, why is it not possible to decorate a property with
> attributes and associations (using the UML terminology)?  I found this
> very frustrating as, for example, a simple mapping between a UML
> Association Class and a OWL Property is not possible.
> Thanks in advance for your clarifications.
> Regards,
> Justo Ruiz Ferrer.
Received on Tuesday, 9 December 2003 13:40:27 UTC

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