- From: Arjohn Kampman <akam@aidministrator.nl>
- Date: Fri, 26 Jan 2001 09:44:33 +0100 (MET)
- To: horrocks@cs.man.ac.uk
- Cc: www-rdf-interest@w3.org
> > Related to this: I think you can state that, for a property to be
transitive,
> > all of its superproperties have to be transitive too.
> >
> > >From the RDF/S spec: "If some property P2 is a subPropertyOf another more
> > general property P1, and if a resource A has a P2 property with a value B,
> > this implies that the resource A also has a P1 property with value B."
> >
> > Now consider P2 to be a transitive property and you have the following
> > situation:
> >
> > X --P2--> Y --P2--> Z
> >
> > In that case, X would also be related to Z through P2 and thus, as P1 is a
> > superproperty of P2, also through P1. Therefore P1 also has to transitive.
> >
> > Please correct me if I'm wrong,
>
> You are wrong I'm afraid. Here is a counter example:
>
> P1 = {(x,y),(y,z),(x,z),(w,x)}
> P2 = {(x,y),(y,z),(x,z)}
> P3 = {(x,y),(y,z)}
>
> As you can see, P3 is a subPropertyOf P2 is a subPropertyOf P1. Only
> P2 is transitive.
I see. So you can derive some statements about P1 (for instance that it
connects X and Z in my example) when its subproperty is transitive, but
P1 itself doesn't have to be transitive.
Arjohn
Received on Friday, 26 January 2001 04:01:46 UTC