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Re: declaredAs

From: Evren Sirin <evren@clarkparsia.com>
Date: Thu, 26 Jul 2007 09:21:36 -0400
Message-ID: <46A89FE0.2090908@clarkparsia.com>
To: Matthew Horridge <matthew.horridge@cs.man.ac.uk>
CC: Owl Dev <public-owl-dev@w3.org>

On 7/25/07 10:13 AM, Matthew Horridge wrote:
> Revisiting the issue of declaring and typing, because it is causing 
> problems - in particular backwards compatibility with OWL 1.0
> Below is a message to the list from Evren Sirin
>> On 26 Jan 2007, at 20:22, Evren Sirin wrote:
>> In OWL 1.0, there is not really a difference between declarations and 
>> typing. Having a triple <p, rdf:type, owl:ObjectProperty>  
>> constitutes its declaration (as on object property in this case). I 
>> agree that requiring declaration for every resource is not a good 
>> idea. OWL-DL requires every resource to be typed and it turns out 
>> that many ontologies out on the Web fall into OWL-DL expressivity but 
>> do not meet this requirement. But now are we separating declarations 
>> from typing and say that declarations are not required but typing 
>> still is?
>> And if I understand the mapping from RDF graphs to OWL 1.1 correctly, 
>> an ontology that has just the above triple (or any any number of 
>> rdf:type triples where the object is one of owl:ObjectProperty, 
>> owl:DatatypeProperty, or owl:Class) will be mapped to an empty OWL 
>> 1.1 ontology. I don't think this is a desired result.
> I am in complete agreement with the last point.  There are plenty 
> (enough to cause problems) of ontologies that just consist of rdf:type 
> triples such as A rdf:type owl:Class.  As Evren points out, when 
> parsed, these documents result in empty ontologies, which is less than 
> desirable - users of tools such as editors find this confusing and 
> don't expect it.  Does anyone have any suggestions about how to 
> resolve this?
My suggestion (which I might have mentioned in the past) is to drop 
owl11:declaredAs keyword completely and use rdf:type instead. In the 
RDF/XML mapping, the triple C rdf:type owl:Class would be mapped to 
Declaration(OWLClass(C)) directly (similarly for properties, individuals 
and datatypes).

> Cheers,
> Matthew
Received on Thursday, 26 July 2007 13:21:48 UTC

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