In the Open World Assumption the existence of further Individuals is possible, if they are not explicitly excluded or forbidden. In the Closed World Assumption it s assumed that the Knowledge Base contains always all Individuals. If there is no Knowledge about an Individual this individual does not exists.
|Knowledge Base||are all children of Hevok female?||no idea since we do not know||If we assume that when know everything about Hevok then all children of Hevok of his children are female|
|child(Hevok,EVA) Female(EVA)||? ⊨ ∀child.Man(Hevok)||DL answers don't know||PROLOG answers yes|
|≤1 child.T(Hevok)||? ⊨ ∀child.Man(Hevok)||yes||now we know everything about Hevok's children|