A Geometrical Characterization of Intrinsic Ultracontractivity for Planar Domains with Boundaries Given by the Graphs of Functions Rodrigo BanuelosBurgess Davis Indiana University Mathematics Journal 1992 text pdf 10.1512/iumj.1992.41.41049 10.1512/iumj.1992.41.41049 en Indiana Univ. Math. J. 41 (1992) 885 - 913 state-of-the-art mathematics http://iumj.org/access/