Poincare Metrics on Real Projective Space Isaac Chavel Indiana University Mathematics Journal 1974 text pdf 10.1512/iumj.1974.23.23007 10.1512/iumj.1974.23.23007 en Indiana Univ. Math. J. 23 (1974) 95 - 101 state-of-the-art mathematics http://iumj.org/access/