Disjoint Sets in Set Theory

A detailed tutorial on disjoint sets. Step by step tutorial including several examples of disjoint sets and how to identify disjoint sets for reference.

A disjoint set is a term applied in set theory when two or more sets have no elements in common. For example, the sets {1, 2, 3} and {7, 8, 9} are disjoint sets because none of the numbers in the sets are the same. The formal way to say this is that two sets are disjoint sets if their intersection creates an empty set, in other words, nothing at all. An intersection is when you only take the values that are found in both sets. If none of the values are the same, this would be an empty set. Disjoint sets can be classified into further categories of piecewise, pairwise, or mutually disjoint provided that in a collection, at least two sets are disjoint.