On arithmetic of the superspecial locus Chia-Fu Yu Indiana University Mathematics Journal 2018 text pdf 10.1512/iumj.2018.67.7436 10.1512/iumj.2018.67.7436 en Indiana Univ. Math. J. 67 (2018) 1341 - 1382 state-of-the-art mathematics http://iumj.org/access/