Corrigendum on 'On the Morse Index Theorem' S. Smale Indiana University Mathematics Journal 1967 text pdf 10.1512/iumj.1967.16.16070 10.1512/iumj.1967.16.16070 en Indiana Univ. Math. J. 16 (1967) 1069 - 1070 state-of-the-art mathematics http://iumj.org/access/