INVARIANT FORMULATION OF CP VIOLATION FOR 4 QUARK FAMILIES

We find a minimal set of constraints which are independent of the choi ce of weak quark basis and necessary and sufficient for CP conservatio n for four quark families, including also the case of degenerate quark masses. These invariant conditions are written in the mass eigenstate basis as a function of the fermion masses and charged current mixings . CP violation is then related to the areas of three unitarity quadran gles and the CP violating effects of the fourth family are discussed i n the case of small mixings.