Local polynomial hulls of discs near isolated parabolic points B. Joricke 32E2032V4032V25Parabolic pointspolynomial hullspolynomial convexitycharacteristic foliationanalytic discssingularities of planar vector fieldsstrong unstable and centre manifolds Indiana University Mathematics Journal 1997 text pdf 10.1512/iumj.1997.46.1501 10.1512/iumj.1997.46.1501 en Indiana Univ. Math. J. 46 (1997) 789 - 826 state-of-the-art mathematics http://iumj.org/access/