Asymptotics for the spectrum of the Dirichlet laplacian on horn-shaped regions M. BergM. Lianantonakis 35P20Dirichelet Laplace operatorasymptoticsspectrumhorn-shaped regions Indiana University Mathematics Journal 2001 text pdf 10.1512/iumj.2001.50.1913 10.1512/iumj.2001.50.1913 en Indiana Univ. Math. J. 50 (2001) 299 - 334 state-of-the-art mathematics http://iumj.org/access/