Image of Analytic Hypersurfaces Shanyu Ji Indiana University Mathematics Journal 1990 text pdf 10.1512/iumj.1990.39.39026 10.1512/iumj.1990.39.39026 en Indiana Univ. Math. J. 39 (1990) 477 - 483 state-of-the-art mathematics http://iumj.org/access/