The Splitting of a (T_1 \oplus T_2) and Related Questions J. ConwayPei Wu Indiana University Mathematics Journal 1977 text pdf 10.1512/iumj.1977.26.26002 10.1512/iumj.1977.26.26002 en Indiana Univ. Math. J. 26 (1977) 41 - 56 state-of-the-art mathematics http://iumj.org/access/