Show by explicit construction that the Pauli-Dirac and chiral representations are related by a unitary transformation, i.e., that there exists a unitary matrix U such that
UγPDμU†=γchμ,UuPD(p,s)=uch(p,s),UvPD(p,s)=−vch(p,s).
(The extra sign in the v-spinor transformation is due to a sign convention.)