Boundaries of locally conformally flat manifolds in dimensions $4k$ Sergiu Moroianu Indiana University Mathematics Journal 2018 text pdf 10.1512/iumj.2018.67.6268 10.1512/iumj.2018.67.6268 en Indiana Univ. Math. J. 67 (2018) 329 - 342 state-of-the-art mathematics http://iumj.org/access/