Quasidiagonal traces and crossed products Marzieh Forough Indiana University Mathematics Journal 2019 text pdf 10.1512/iumj.2019.68.7759 10.1512/iumj.2019.68.7759 en Indiana Univ. Math. J. 68 (2019) 1579 - 1590 state-of-the-art mathematics http://iumj.org/access/