The projective theory of relativity

Introduction. – In what follows, one will find a summary of the projective theory of relativity, as it was developed in the publications G. F. III, IV, V, VI, VIII (), upon starting with the idea, which is due to O. VEBLEN and B. HOFFMANN (), of a projective connection that leaves invariant a given quadric in local space. As in those publications, we shall make use of the method of homogeneous coordinates that is due to van DANTZIG ()(). Meanwhile, the theory and calculations have been simplified greatly by introducing the signature − − − − + for the fundamental projector Gλκ directly and employing auto-geodesics, instead of the induced geodesics that were utilized in G. F. III-VI (). We have also employed the RICCI symbolism in its most modern form, as