Generic Homotopies of Immersions George Francis Indiana University Mathematics Journal 1972 text pdf 10.1512/iumj.1972.21.21088 10.1512/iumj.1972.21.21088 en Indiana Univ. Math. J. 21 (1972) 1101 - 1112 state-of-the-art mathematics http://iumj.org/access/