Gravitational Mass

The Gravitational Mass ofa Body is exactly equall to it's inertial mass. Extensive testing over the last centuryon earth shows this to be true for our local spacetime. We have not tested this in energetically dense spacetimes. Special relativity implies that the inertial mass of a physical system increases with the total energy of the system. Even pure light has a relative energectic mass as shown by its maximum moving velocity throughout space time.