| Enter the set A(superset) | = |
| Enter the set B | = |
| The set B is | = of set A |
In mathematics, especially in set theory, a set A is a subset of a set B, or equivalently B is a superset of A, if A is "contained" inside B, that is, all elements of A are also elements of B. A and B may coincide. The relationship of one set being a subset of another is called inclusion or sometimes containment.
The subset relation defines a partial order on sets. The algebra of subsets forms a Boolean algebra in which the subset relation is called inclusion.
If A and B are sets and every element of A is also an element of B, then: A is a subset of (or is included in) B, denoted by A B
Some basic properties of unions: