The set of elements belonging to one but not both of two given sets. It is therefore the union of the complement of A with respect to B and B with respect to A, and corresponds to the XOR operation in Boolean logic. The symmetric difference can be implemented in the Wolfram Language as: SymmetricDifference[a_, b_] := Union[Complement[a, b], Complement[b, a]]

complement set | difference | set difference | union | XOR