The defect of Bennequin-Eliashberg inequality and Bennequin surfaces Keiko Kawamuro Indiana University Mathematics Journal 2019 text pdf 10.1512/iumj.2019.68.7662 10.1512/iumj.2019.68.7662 en Indiana Univ. Math. J. 68 (2019) 799 - 833 state-of-the-art mathematics http://iumj.org/access/