RIEMANNIAN-MAXWELLIAN INVERTIBLE STRUCTURES IN GENERAL-RELATIVITY

It is shown that a space-time admitting a nonsingular 2-form satisfying the source-free Maxwell equations and a Lorentzian involution under which the 2-form and the exterior derivative of a related 2-form are skew invariant while the trace-free Ricci tensor and the covariant derivative of the involution itself are invariant possesses locally an invertible 2-parameter Abelian isometry group with nonsingular orbits. © 1979 Plenum Publishing Corporation.