Deformations of Linear Connections and Riemannian Manifolds M. Raghunathan Indiana University Mathematics Journal 1964 text pdf 10.1512/iumj.1964.13.13006 10.1512/iumj.1964.13.13006 en Indiana Univ. Math. J. 13 (1964) 97 - 123 state-of-the-art mathematics http://iumj.org/access/