A Generalization of the Alexander Duality Theorem W. Massey Indiana University Mathematics Journal 1981 text pdf 10.1512/iumj.1981.30.30037 10.1512/iumj.1981.30.30037 en Indiana Univ. Math. J. 30 (1981) 467 - 477 state-of-the-art mathematics http://iumj.org/access/