The Eötvös parameter h , which quantifies the violation of equivalence for two bodies of composition A and B, inertial mass mi and gravitational mass mg,  can be generalized into:

Each  hk ¹ 0   would define a violation of Equivalence between the inertial and gravitational mass-energy of the k-th type.  If the Equivalence Principle holds, all these separate Equivalence Principles must hold,  corresponding  to a very peculiar coupling of each field to gravity (true only for the gravitational interaction!!!).

Scientific relevance of the Equivalence Principle (II)