The whole containing no proper parts: this concept is useful in domain ontologies which assume atomicity, say that there are irreducible objects in the domain (eg, an ontology for the storage of original, pre-packaged car accessories versus an ontology for car parts recycling dealers).
(Slot-Cardinality *Atomic-Whole _Atom 1) (<=> (*Atomic-Whole ?Self) (And (Object ?Self) (Value-Cardinality ?Self _Atom 1)))