Hyperinvariant Subspaces of C_11 Contractions, II Pei Wu Indiana University Mathematics Journal 1978 text pdf 10.1512/iumj.1978.27.27053 10.1512/iumj.1978.27.27053 en Indiana Univ. Math. J. 27 (1978) 805 - 812 state-of-the-art mathematics http://iumj.org/access/