Union (∪)

Definition

The union of two sets, denoted by the symbol ∪, is the set that contains all elements that are in either or both of the original sets. It represents the combination of all unique elements from the given sets, without any duplicates.

5 Must Know Facts For Your Next Test

1. The union of two sets A and B is denoted as A ∪ B and includes all elements that are in either A, B, or both.
2. The union of two disjoint sets results in a set that contains all the unique elements from both sets.
3. The union operation is commutative, meaning A ∪ B = B ∪ A.
4. The union operation is associative, allowing for the grouping of sets in any order, such as (A ∪ B) ∪ C = A ∪ (B ∪ C).
5. The union of a set with the empty set (∅) results in the original set, as ∅ ∪ A = A.

Review Questions

• Explain the concept of the union of two sets and how it differs from the intersection of two sets.
  • The union of two sets, A and B, is the set that contains all elements that are in either A, B, or both. It represents the combination of all unique elements from the given sets, without any duplicates. In contrast, the intersection of two sets is the set that contains only the elements that are common to both A and B. While the union includes all elements from both sets, the intersection includes only the elements that are shared between the two sets.
• Describe the properties of the union operation, including commutativity and associativity.
  • The union operation has several important properties. First, it is commutative, meaning the order of the sets does not matter, and A ∪ B = B ∪ A. Additionally, the union operation is associative, allowing for the grouping of sets in any order, such that (A ∪ B) ∪ C = A ∪ (B ∪ C). Finally, the union of a set with the empty set (∅) results in the original set, as ∅ ∪ A = A. These properties of commutativity and associativity make the union operation a powerful tool for working with sets.
• Analyze the relationship between the union, intersection, and complement of sets, and explain how they can be used together to describe set relationships.
  • The union, intersection, and complement of sets are closely related and can be used together to describe the relationships between sets. The union of two sets, A ∪ B, represents all the elements that are in either A, B, or both. The intersection of two sets, A ∩ B, represents the elements that are common to both A and B. The complement of a set, A', contains all the elements that are not in set A. By understanding and applying these set operations, you can determine the unique elements, common elements, and non-overlapping elements between different sets, which is essential for analyzing and interpreting Venn diagrams.

Related terms

Intersection (∩): The intersection of two sets is the set that contains all elements that are common to both sets.

Complement (A'): The complement of a set A is the set that contains all elements that are not in set A.

Disjoint Sets: Two sets are considered disjoint if they have no elements in common, meaning their intersection is an empty set.