Field equations and relations | Field functions, 4-currents |

Field equations | Divergences of field tensors, 4-currents |

Motion equation | Products of field tensors and 4-currents or divergences of fieldsâ€™ stress-energy tensors |

Energy, Lagrangian, Hamiltonian | 4-potentials, field tensors and 4-currents |

Equation for the metric | The Ricci tensor, scalar curvature, fieldsâ€™ stress-energy tensors |

Gauge of 4-potentials | Divergences of 4-potentials |

Continuity equations | Divergences of 4-currents, field tensors, the Ricci tensor |