Do these two expressions mean the same? So for a given database we have the sets Persons, Married, Women, Men and Children. I want to express all Women who are not Children and not Married: $$Women\setminus \left ( married \cup children \right )$$ $$Women \setminus \left ( \overline{married} \cap \overline{children} \right )$$ Do these set operations qualify as Women who are not Children or Married, and express the same?

Yes, both give you the set you want and they are equivalent by the De Morgan's laws.