Explicit rephasing transformation of four-generation mixing matrix and formulae for CP phases

In this letter, we present an explicit rephasing transformation that maps a general $4\times4$ flavor mixing matrix to the standard parametrization of four-generation models. By combining rephasing-covariant minors and the determinant systematically, we derive expressions for all three Dirac-type CP phases, three Majorana phases, and four unphysical phases by arguments of matrix elements. The resulting formulae smoothly reduce to the three-generation results in the limit where the fourth generation decouples.