In this article we give a complete proof in one dimension of an a priori inequality involving pseudo-differential operators: if and are symbols in such that , then for all we have the estimate for all in the Schwartz space, where is the usual norm. We use microlocalization of levels I, II and III in the spirit of Fefferman’s SAK principle.
We give an explicit expression of a two-parameter family of Flensted-Jensen’s functions on a concrete realization of the universal covering group of . We prove that these functions are, up to a phase factor, radial eigenfunctions of the Landau Hamiltonian on the hyperbolic disc with a magnetic field strength proportional to , and corresponding to the eigenvalue .
The paper deals with quarkonial decompositions and entropy numbers in weighted function spaces on hyperbolic manifolds. We use these results to develop a spectral theory of related Schrödinger operators in these hyperbolic worlds.