[protege-discussion] An interesting pizza... or max and exactly cardinality not working?

[maarten]

Dear Thomas,

Thanks for the interesting links. Things make more sense now. This open 
world semantics is sometimes confusing. However, my main problem I 
realise is that I was considering types, instead of individuals e.g.:

1. Pizza and hasTopping exactly 2 CheeseTopping

I understood as:

2. Pizza and hasTopping exactly 2 /types of/ CheeseTopping

Having pizzas with two (disjoint) cheese toppings in a closed 
definition, I couldn't figure out why the reasoner couldn't classify the 
pizza. So, it is all about individuals. Makes sense (also).
Of course, in 1. you can never be sure that a pizza doesn't have 3 
mozzarella toppings of instance.

Thanks again,

Maarten




Thomas Russ wrote:
>
> On Sep 7, 2009, at 1:58 AM, maarten wrote:
>
>>
>> Hi all,
>>
>> Studying the pizza.owl, I didn't get cardinalities max or exactly to 
>> work the way I expected.
>>
>> An interesting pizza has the following equivalent class: Pizza and 
>> hasTopping min 3 Thing
>>
>> When I change this (or create a similar pizza) with 'max' or 
>> 'exactly' instead of 'min', I don't get the expected result (e.g. all 
>> pizzas with 3 or less toppings, or exactly 3 toppings).
>>
>> I'm quite new to owl modeling and protege 4, so I'm probably missing 
>> something.
>
> Open world semantics.
>
> If you search on the protege-owl mailing list archives, this comes up 
> quite frequently.
>
> For example:
>
>   
> http://thread.gmane.org/gmane.comp.misc.ontology.protege.owl/25589/focus=25624 
>
>   
> http://thread.gmane.org/gmane.comp.misc.ontology.protege.owl/18189/focus=18213 
>
>   
> http://thread.gmane.org/gmane.comp.misc.ontology.protege.owl/23735/focus=23745 
>
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