Mathisson-Papapetrou Equations as Conditions for Compatibility of General Relativity and Continuum Physics

In continuum physics is presupposed that general-relativistic balance equations are valid which are created from the Lorentz-covariant ones by application of the equivalence principle. Consequently, the question arises, how to make these general-covariant balances compatible with Einstein's field equations. The compatibility conditions are derived by performing a modified Belinfante-Rosenfeld symmetrization for the non-symmetric and not divergence-free general-relativistic energy-momentum tensor. The procedure results in the Mathisson-Papapetrou equations.