Über Gitter in der hyperbolischen Ebene.
Unbounded harmonic functions on homogeneous manifolds of negative curvature
We study unbounded harmonic functions for a second order differential operator on a homogeneous manifold of negative curvature which is a semidirect product of a nilpotent Lie group N and A = ℝ⁺. We prove that if F is harmonic and satisfies some growth condition then F has an asymptotic expansion as a → 0 with coefficients from 𝓓'(N). Then we single out a set of at most two of these coefficients which determine F. Then using asymptotic expansions we are able to prove some theorems...
Universal bounds for eigenvalues of Schrödinger operators on Riemannian manifolds.
Untermannigfaltigkeiten reduktiver Räume
Untermannigfaltigkeiten von homogenen Räumen