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Re: declaredAs

From: Matthew Horridge <matthew.horridge@cs.man.ac.uk>
Date: Thu, 26 Jul 2007 14:35:59 +0100
Message-Id: <34DC6931-33FE-4D48-BC13-52DF4B7062FF@cs.man.ac.uk>
To: Owl Dev <public-owl-dev@w3.org>

On 26 Jul 2007, at 14:21, Evren Sirin wrote:

> 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).

I completely agree.

Received on Thursday, 26 July 2007 13:36:14 UTC

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