The Elementary Basic Principles of the Unified Theory of Relativity. C_4 General Case Vaiclav Hlavaty Indiana University Mathematics Journal 1956 text pdf 10.1512/iumj.1956.5.55016 10.1512/iumj.1956.5.55016 en Indiana Univ. Math. J. 5 (1956) 419 - 472 state-of-the-art mathematics http://iumj.org/access/