An actor can only have associations to use cases, components, and classes. Furthermore these associations must be binary.

self.ownedAttribute->forAll ( a |
(a.association->notEmpty()) implies
((a.association.memberEnd.size() = 2) and
(a.opposite.class.oclIsKindOf(UseCase) or
(a.opposite.class.oclIsKindOf(Class) and not a.opposite.class.oclIsKindOf(Behavior))))

randomness