Sharp Spectral Asymptotics for four-dimensional Schroedinger operator   with a strong magnetic field. II
  I consider 4-dimensional Schr\"odinger operator with the generic non-degenerating magnetic field and for a generic potential I derive spectral asymptotics with the remainder estimate $O(\mu^{-1}h^{-3})$ and the principal part $\asymp h^{-4}$ where $h\ll 1$ is Planck constant and $\mu \gg 1$ is the intensity of the magnetic field. For general potentials remainder estimate $O(\mu^{-1}h^{-3}+\mu^2h^{-2})$ is achieved. 
Victor Ivrii