For example, consider the set of positive even numbers, and the set of positive multiples of 3. The symmetric difference of these two sets is the set {2, 3, 4, 8, 9, 10, 14, 15, 16, ...}

# symmetric difference (idea)

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In set theory, the symmetric difference of two sets A and B is the set of elements which appear in exactly one of A or B. In other words, it is the union of A and B minus their intersection. This operator is both commutative and associative. It is usually represented by an uppercase delta.