Re: OWL DL extension question

On 3/21/07 1:55 PM, Conrad Bock wrote:
> DLers,
>
> Was wondering if anyone is looking into whether this fragment can be
> added tractably to OWL DL (1.0):
>
>   (forall (x y z)
>      (if (and (P x y)
>               (R x z))
>          (S y z)))
>
> For example, the uncles of my children include all my brothers
> (P=children, R=brothers, S=uncles).
>   
You can turn the antecedent into a property chain using the inverse of P 
and then use the standard complex role inclusions of OWL 1.1 as:

SubObjectPropertyOf(SubObjectPropertyChain(InverseObjectProperty(children) 
brothers) uncles)

provided that the restrictions described at [1] are not violated.
> My understanding is this is different from general role inclusion:
>
>   (forall (x y z)
>      (if (and (P x y)
>               (R y z))
>          (S x z)))
>
> For example, my brothers include all the uncles of my children
> (P=children, R=uncles, S=brothers).
>   
You are correct that this inclusion axiom is saying something slightly 
different.

Regards,
Evren

[1] http://owl1_1.cs.manchester.ac.uk/owl_specification.html#7
> Conrad
>
>
>
>
>