Electromagnetic origin of mass due to folded pseudo-coordinates
  Nullification of the Einstein tensor curvature for the elementary material space with active gravitational field (radial source) and passive field distribution of its inertial particle (radial sink) maintains the conceptual equivalence of collinear active and passive energy-momentum densities of the nonlocal energy-matter carrier in General Relativity (GR). The Ricci scalar curvature in the Lagrangian for electron's material space is related to active and passive real mass densities with residual positive energy, while electromagnetic (EM) active and passive imaginary mass densities produce a traceless energy density. One four-potential in geometrical sink-source identities universally forms gravitational and electromagnetic fields of the complex mass current. EM vector equalities balance anti-collinear four flows of active and passive imaginary masses (called electric charges). Similar GR vector equalities take into account twin coupling of inseparable unlike mass densities existing due to the forth-coordinate symmetry, $ dt = |\pm idx^4/c|$, in the Minkowski four-interval. Two equal pseudo-coordinates $\pm ix^o\equiv \pm x^4 $ serve for equal unlike masses of the same inertial body that results in collinear active and passive four-currents of real masses with net energy-momentum for collisions and measurements. Couples of unlike twin masses can simultaneously radiate-absorb paired vector waves with zero-balanced Poynting flows for real-time observations in the two-body gravitational system. Such paired vector waves form tensor gravitons which cannot be screened by third bodies or intercepted by interferometers. 
I.E. Bulyzhenkov