Space, Time, Matter

according æther affine geometry arbitrary assume co-efficients co-ordinate system co-variant condition congruent transference const constant corresponding curvature definite denotes density derived determined differential form direction dx² Einstein Einstein's Theory electric electron energy Euclidean geometry Euclidean space expressed force formula four-dimensional function fundamental geodetic gik's gravitational equations gravitational field hence inertial infinitely near points infinitesimal integral invariant light-ray linear form manifold mass mathematical matter Maxwell's Maxwell's equations means measure mechanics metrical field metrical groundform metrical space metrical structure motion parallel displacement particle phase-quantities physical laws plane point-mass positive potential principle of relativity quadratic differential quadratic form quantities radius respect result Riemann rotation scalar second order sphere statical straight line surface symmetrical tensor tensor-density theorem theory of relativity transformation vanish variables variation vector velocity vide note world-line world-point дхі дхк