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[protege-owl] Property cardinality exactly 0: is this correct?
tar at ISI.EDU
Fri Aug 3 09:28:29 PDT 2007
On Aug 3, 2007, at 8:05 AM, João Olavo Baião de Vasconcelos wrote:
> I've this situation: a class A that has many classes under it.
> Class A is related to class B by the property P. But I want to say
> that one of A subclasses (C) is not related to B.
> As I didn't add any cardinality restriction, it means that one A is
> related to 0 or more Bs.
> So, I'm thinking in add a new restriction to C that says: P exactly
> 0. That is, a C is related to 0 Bs.
> Is there any problem doing this?
> Will it be a problem for a reasoner?
This is all fine.
As long as the restrictions you add to subclasses are more specific,
then things are good. What you are not allowed to do (in a
consistent KB) is to introduce disjoint restrictions. You CAN write
more general restrictions, but they won't have any effect, since the
inherited more specific ones will take precedence.
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