Gauge-periodic point perturbations on the Lobachevsky plane

We study periodic point perturbations of the Shrodinger operator with a uni form magnetic field on the Lobachevsky plane. We prove that the spectrum ga ps of the perturbed operator are labeled by the elements of the K-0 group o f a C* algebra associated with the operator. In particular, if the C* algeb ra has the Kadison property, then the operator spectrum has a band structur e.