High Quality Content by WIKIPEDIA articles! In set theory, a complement of a set A refers to things not in (that is, things outside of), A. The relative complement of A with respect to a set B, is the set of elements in B but 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 all elements in U but not in A.If A and B are sets ...Full description
High Quality Content by WIKIPEDIA articles! In set theory, a complement of a set A refers to things not in (that is, things outside of), A. The relative complement of A with respect to a set B, is the set of elements in B but 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 all elements in U but not in A.If A and B are sets, then the relative complement of A in B, also known as the set-theoretic difference of B and A, is the set of elements in B, but not in A.The relative complement of A in B is denoted B ¿ A (sometimes written B ¿ A, but this notation is ambiguous, as in some contexts it can be interpreted as the set of all b ¿ a, where b is taken from B and a from A).