self.slot->select(sl : SlotType1 | (not sl.name.oclIsUndefined()) and sl.name = 'authorPerson')->size()<2 and 
	self.slot->select(sl : SlotType1 | (not sl.name.oclIsUndefined()) and sl.name = 'authorPerson')->forAll(sl : SlotType1 | 
		(not sl.valueList.oclIsUndefined()) and sl.valueList.value->size()<2  )