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Re: OWL and Vocabularies

From: Benjamin Nowack <bnowack@appmosphere.com>
Date: Tue, 24 Feb 2004 17:32:07 +0100
To: "Rory Galvin" <galvinr@tcd.ie>
Cc: <www-rdf-logic@w3.org>
Message-ID: <PM-EH.20040224173207.59F7A.1.1D@>

On 24.02.2004 15:28:54, Rory Galvin wrote:
>If I use OWL DL does that mean I cannot create instances of classes? Do I
>have to refer to instances as subclasses?
ah, no. DL has many restrictions, but not that many ;-) sorry if I 
confused you.
In OWL DL ontologies, classes, properties, individuals and annotation
properties have to be disjoint, i.e. you can't describe a class and then
use this "class description" as an individual.
e.g. if you want to say that your class description has the dc:creator
"Rory Galvin", you have to explicitly type dc:creator as 
owl:AnnotationProperty in OWL DL.

But you can certainly create class "instances" (=individuals). that's
what the ontology stuff is for.

>If I decide to use dublin core and I describe all elements as Annotation
>properties will I not be able to specify the range and domain of those
>properties because they are annotation properties?
exactly. in OWL DL you can't further describe annotation properties. so,
if you specify range and domain, you are in OWL Full space. but this is
IMHO only a problem if you are using a DL reasoner. in any other case
OWL Full is just fine, it's closer to all the RDF already out there..
(the much bigger problem is to find agreed-on and shared domains and 
ranges for DC terms..)


Benjamin Nowack

Kruppstr. 82-100
45145 Essen, Germany
Received on Tuesday, 24 February 2004 11:32:21 UTC

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