Counterintuitive transitions in the multistate Landau-Zener problem with   linear level crossings
  We generalize the Brundobler-Elser hypothesis in the multistate Landau-Zener problem to the case when instead of a state with the highest slope of the diabatic energy level there is a band of states with an arbitrary number of parallel levels having the same slope. We argue that the probabilities of counterintuitive transitions among such states are exactly zero. 
N. A. Sinitsyn