The Classical Theory of Fields, Том 1

angle angular momentum arbitrary average axes axis body calculate Christoffel symbols components condition consider const constant coordinate system corresponding covariant covariant derivative curvature tensor curvilinear coordinates denote density derivatives determined differentiation dipole direction distance ds² dx¹ Einstein equations electromagnetic field energy energy-momentum tensor equal equations of motion expressed in terms field produced finite formula four-dimensional four-momentum four-vector four-velocity Fourier frequency function galilean geometrical optics given gravitational field hypersurface infinity integral intensity interval Lagrangian magnetic field mass metric tensor obtain optical P₁ particle polarization problem propagation quantities radiation radius vector rays reference frame reference system relation rotation scalar Schwarzschild sin² singularity solution space space-time spatial Substituting system of charges system of reference three-dimensional transformation values vanish vector potential wave surface wave vector world line write zero αβ