Sets

4. The Union of Sets

The union of set A and B, is the set which consists of elements that are either in A or B or both. The set notation for the operation of union is ⋃. Thus, A union B is written

A ⋃ B.

In set theoretical notation,

A ⋃ B = {X : X ∈ A, or X ∈ B or X ∈ both A and B}.

Example

Given that G= {h, e, a, p}, H = {l, a, k, e} then,

G ⋃ H = {h, e, a, p, l, k}

If X= {2, 4, 6, 8}, Y = {2, 5, 9, 11, 12}

Then X ⋃ Y = {2, 4, 5, 6, 8, 9, 11, 12}