Abstract: The subject of the talk is a spinless particle in a homogeneous
magnetic field whose motion is restricted to a layer with Dirichlet boundary
conditions perpendicular to the field. The presence of a periodic family of point
interactions causes a change of the spectrum which will contain bands in addition
to the generalized Landau levels. Using the Landau-Zak transformation together with
Krein's formula we are able to describe these bands and find their number
in the case of a rational flux through the elementary cell.