Re: Subsumption question

Hi Matthew,

On 29 Apr 2009, at 22:06, Matthew Graham wrote:

> Hi,
>
> I'm new to OWL and am still trying to get my head around some stuff  
> so apologies if this email seems to be asking a dumb question. I'm  
> also sending this message to this list since I think it is about OWL  
> in general.
>
> I'm using the latest version of Protege to work on my ontology and  
> have the following issue:
>
> Classes: StellarObject (subclass of AstrObject), StellarTypeK  
> (subclass of ClassificationCategory), StellarTypeM (subclass of  
> ClassificationCategory)
>
> Properties: isClassifiedAs (domain: AstrObject, range:  
> ClassificationCategory)
>
> A class BYDraconis has an inherited anonymous class: StellarObject  
> and isClassifiedAs some (StellarTypeK or StellarTypeM).

You mean, it is an inherited _sub_class of "StellarObject and  
isClassifiedAs some (StellarTypeK or StellarTypeM)"?
>
>
> I am making a class query with DL Query looking for: StellarObject  
> and isClassfiedAs some StellarTypeK
> but it is not matching BYDraconis. So why generally is "Class and  
> myProperty some A" not a subclass of "Class and myProperty some (A  
> or B)" ?

The former _is_ a subclass of the latter. So your general statement is  
right.

> How should I be modelling this so that it does what I want?

I think there's a little bit of confusion between super- and  
subclasses here:

* Are you looking for _sub_classes of "StellarObject and isClassfiedAs  
some StellarTypeK"? Then BYD can't be returned because it is a  
subclass of
StellarObject and isClassifiedAs some (StellarTypeK or StellarTypeM),  
which in turn is not a subclass of StellarObject and isClassfiedAs  
some StellarTypeK. (This would be the converse of your general  
statement.)

* Or are you looking for _super_classes of "StellarObject and  
isClassfiedAs some StellarTypeK"? Then BYD can only be returned if it  
is an inherited _super_class of "StellarObject and isClassifiedAs some  
(StellarTypeK or StellarTypeM)", which is indeed a superclass of  
"StellarObject and isClassifiedAs some (StellarTypeK or  
StellarTypeM)", as per your general statement.

Hope this helps

Thomas

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|  Dr Thomas Schneider                         schneider@cs.man.ac.uk  |
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Received on Thursday, 30 April 2009 09:01:23 UTC