Re: Question on special class description

I would think that getting a complete definition for GoodParent would
be difficult due to the open world assumption, unless techniques are
applied to close the hasChild and loves relations.  Otherwise, the OWA
would say that there might be children we don't know about, which
aren't loved.  Or, for the negative (not GoodParent), a child that is
known, but not known to be loved, might be loved.

That said, a partial definition would be possible in OWL 2:

    GoodParent => isGoodParent some Self
    isGoodParent o hasChild => loves

-Brandon :)

On Tue, Feb 23, 2010 at 2:10 PM, Thomas Schneider <schneidt@cs.man.ac.uk> wrote:
> Hi Lennart,
>
> I can only see two ways, and they lead out of OWL-DL, but perhaps someone
> else here has a better idea?
>
> (1) If you use Boolean operators on roles, you can define a new role
> hasChildButDoesNotLoveIt to be "hasChild and not loves". You can then define
> the desired class as GoodParent = hasChildButDoesNotLoveIt only Nothing.
>
> (2) If you define a new property p to be a superproperty of the chain
> "hasChild o inv(loves)", then you can define a GoodParent to be equivalent
> to not p some Self. Unfortunately, only simple object property expressions
> are allowed in hasSelf restrictions and p is composite due to the first
> statement.
>
> I suppose this doesn't really help ... :-S
>
> Cheers
>
> Thomas
>
> On 23 Feb 2010, at 15:35, Lennart Bierkandt wrote:
>
>> Hello,
>>
>> I am developing an ontology for a linguistic typological database, where I
>> need to describe a class of the form:
>> { x | ∀y( r1(x,y) -> r2(x,y) ) }
>> As explaining the real use of this would be to complicated, imagine a
>> class denoting e.g. "people who love (r2: loves) all their children (r1:
>> hasChild) (or haven't any)".
>>
>> In prose it doesn't seem to be too complex, but I didn't find a way to do
>> it..
>> CAN this be expressed in OWL-DL? and if, how? (and if not, in OWL-FULL?)
>>
>> Kind regards,
>> Lennart Bierkandt
>>
>>
>>
>
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Received on Tuesday, 23 February 2010 19:56:36 UTC