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[protege-owl] instances inferring
tar at ISI.EDU
Thu Apr 26 12:02:03 PDT 2007
On Apr 26, 2007, at 9:19 AM, Abrami Géraldine wrote:
> As far as I understood the Open World Assumption, when I create a
> new “empty” class (without restrictions) MyNewClass directly under
> owl:thing and run the reasonner I thought that all individuals
> would have been classified in this MyNewClass.
> Why does this not happen?
Because there is no reason to support them being members of the class.
By having a "empty" class without any restrictions, you have created
a primitive class. In the absence of sufficient conditions, there is
no way that any reasoner can infer membership in the class. The only
way to be a class member is to be asserted as a member. [Note,
assertion to a subclass also works, since that is a sufficient
condition for membership in the parent.]
The open world assumption doesn't have anything to do with this.
What open world means is that one cannot use the absence of
information to prove a negation. It applies to constructs like NOT
(Complement) or ONLY (AllValuesFrom) and Max cardinality. Open world
doesn't increase the set of things that can be inferred, rather it
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