  A symmetric union of two knots is a classical construction in knot theory
which generalizes connected sum, introduced by Kinoshita and Terasaka in the
1950s. We study this construction for the purpose of finding an infinite family
of hyperbolic non-fibered three-bridge knots of constant determinant which
satisfy the well-known cosmetic crossing conjecture. This conjecture asserts
that the only crossing changes which preserve the isotopy type of a knot are
nugatory.
