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Re: Inverse property on classes

by thiebal :: Rate this Message:

Thanks for your help Pavel :)

So even if I use cardinality, it won't be different?
:Pizza_mozzarella_class :hasTopping exactly 1 :Mozzarella_class

Would you use allValuesFrom to create this weird pizza class that has all mozzarella as topping?

:Pizza_mozzarella_class :hasTopping all :Mozzarella_class

Actually, I want to use classes and not individuals because I need to reason on them and it seems that reasoners can only work on classes... But it is a lot simpler to work with properties between instances (at least if we want to use inverse and transitive properties) than between classes.

Regards,

Cedric

On Wed, May 13, 2009 at 4:40 PM, Pavel Klinov <klinovp@...> wrote:

Hello,

Cédric Thiébault wrote:

Hi,

[snip]

When I create an individual :Pizza_mozzarella and add a property :hasTopping on :Mozzarella individual, I can work with the inverse property on the topping and I see that :Mozzarella :isToppingOf :Pizza_mozzarella. It works great with individual.

But when I try to do the same test with classes:
:Pizza_mozzarella_class :hasTopping some :Mozzarella_class

But I cannot use the inverse property: :Mozzarella_class does not know anything about :Pizza_mozzarella_class.

Is this normal ?

Yes. Notice that you are not making any claim here about Mozzarella_class in general. You're only saying that all instances of Pizza_mozzarella_class are related to *some* instance of Mozzarella_class. Imagine a model in which there are 10,000 mozarrellas and only one of them is used as a topping on all pizzas (it would be a satisfying model). Would you want to be able to conclude something general about 9,999 mozarellas basing on only one instance?

Are inverse properties usable only on individuals ?

Well, it depends on what you mean by "using". For example, you can define a class (and an instance) of pizzas which has *all* instances of Mozzarella as toppings (although it's not that trivial). Then, of course, you'll be able to infer that :Mozzarella_class :isToppingOf some :that_weird_pizza_class.

Cheers,
Pavel

Thanks for your help :-)

Cedric

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