Re: Property chain axioms and cyclic dependencies

This is tricky, read very carefully the OWL spec.  There are obscure and
bizare (from a common sense user perspective) restrictions that result from
the inference needs.  Good luck.

On Wednesday, May 29, 2013, Matías Parodi wrote:

> Hello,
>
> I'm trying to understand in which cases it's allowed to use
> owl:propertyChainAxiom and when it's not.
>
> I've written a small ontology to understand it (I pasted it at the end),
> but I still couldn't figure out why HermiT (using Protege) says "The given
> property hierarchy is not regular" and "There is a cyclic dependency
> involving property :isRelative".
>
> I know there's a loop there but what is the real problem? After all, how
> is that different from a owl:TransitiveProperty? Any way to intuitively
> understand what is wrong with it?
>
> Any idea?
>
> Thank you,
> Matt
>
> ---
> @prefix : <http://foo/bar#>.
> @prefix owl: <http://www.w3.org/2002/07/owl#>.
> @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
> @prefix xsd: <http://www.w3.org/2001/XMLSchema#>.
>
> :Person a owl:Class.
>
> :isRelativeOf
>   a owl:TransitiveProperty;
>   rdfs:domain :Person;
>   rdfs:range :Person;
> ..
>
>   :isAncestorOf
>     rdfs:subPropertyOf :isRelativeOf;
>     owl:propertyChainAxiom (:isRelativeOf :isAncestorOf);
>   .
> ---
>


-- 
Sent from an input-challenged device.