Protege exactly 1 cardinality OWL restriction not raising an inconsistency

Question

I think I am going crazy! I have followed the various tutorials for Owl and Protege and still cannot figure out the answer. Use case is simple. I have defined a class called ‘Pe

Answer 1

There's no inconsistency in the first case. OWL makes the open world assumption, which means that something being unknown is different from it being known to be true or known to be false. Your username, at the time I'm writing this answer is user3552593. I'm relatively confident that you have a name, and that's not inconsistent with the fact that I don't know what it is yet.

By saying that

Person ⊑ =1 hasFirstName.String

and that

Alex : Person

you can infer that

Alex : =1 hasFirstName.String

There's nothing inconsistent with that; Alex, by virtue of Alex's personhood, has exactly one first name—we just don't know what it is yet.