Re: owl:Class and owl:Thing

Hans Teijgeler wrote:

> In OWL-Full it is possible to have a class that also is an individual in 
> the context of a class-of-class. We have that a lot. Now my question is 
> whether or not I shall call the same object an owl:Class when it is in 
> the role of class, and call it an owl:Thing when it is in the role of 
> individual. If not, what shall prevail? Or must I declare it twice?

You don't *need* to declare it at all in OWL/full.

If you use a resource in the role of a class then it can be inferred to 
be a class. For example, if you use it as the object of an rdf:type 
statement or in an rdfs:subClassOf statement then it can be inferred to 
be an rdfs:Class. In OWL/full rdfs:Class and owl:Class have the same 

Similarly it can be inferred to be an owl:Thing (for trivial reasons in 
OWL/full) and probably some subclass of owl:Thing based on the 
domain/range of whatever properties you apply to it.

However, it may be useful for human readers of your ontology if you 
document it's dual nature by declaring both it's types explicitly along 
with appropriate rdfs:comments.


Received on Thursday, 30 March 2006 21:57:50 UTC