# Union

## Redirected from Union (set theory)

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In set theory, the union of two sets $A,B$ is the set of all elements in $A$ , in $B$ , or both.

Definition

Given two sets $A,B$ ,
$A\cup B=\{x|x\in A\or x\in B\}$

## Example

Suppose $A=\{w,x,y\}$ and $B=\{t,x,z\}$ :

$A\cup B=\{t,w,x,y,z\}$