Graphical representations of sets that help determine the results of set operations visually. For example, a Venn diagram depicting two intersecting sets consists of two slightly overlapping circles. The overlapping regions represent the intersection of the sets.

A representation for sets useful when the universe is small and known. Each member in the universe is represented as a bit in an array. If a member exists in the set, its bit is set to 1; otherwise, its bit is set to 0.

Sets in which members may be duplicated. In some problems the restriction of no duplicate members is too strict. A multiset is an alternative type of set for these problems.