We study the behavior of maximal geodesics outside a sufficiently large compact set in a finitely connected, complete and noncompact 2-dimensional Riemannian manifold (possibly with boundary). One of our main results states that if the total curvature of [italic]M exists and is …
This memoir develops the spectral theory of the Lax operators of nonlinear Schrödinger-like partial differential equations with periodic boundary conditions. Their special curves, i.e., the common spectrum with the periodic shifts, are generically Riemann surfaces of infinite ge…
Fuchsian groups play a central role in various important fields of mathematics. The current book is based on what became known as the famous Fenchel-Nielsen manuscript. Jakob Nielsen (1890-1959) started this project well before World War II, Werner Fenchel (1905-1988) joined lat…
"This is an introductory textbook on isometry groups of the hyperbolic plane. Interest in such groups dates back more than 120 years. Examples appear in number theory (modular groups and triangle groups), the theory of elliptic functions, and the theory of linear differential eq…