Complement (set theory)

In set theory, the complement of a set A, often denoted by Ac (or A′), are the elements not in A. When all sets under consideration are considered to be subsets of a given set U, the absolute complement of A is the set of elements in U that are not in A. The relative complement of A with respect to a set B, also termed the set difference of B and A, written B \ A, is the set of elements in B that are not in A.

Complement (set theory)

In set theory, the complement of a set A, often denoted by Ac (or A′), are the elements not in A. When all sets under consideration are considered to be subsets of a given set U, the absolute complement of A is the set of elements in U that are not in A. The relative complement of A with respect to a set B, also termed the set difference of B and A, written B \ A, is the set of elements in B that are not in A.