  Motivated by the recent advances in studying Majorana states in nanowires
under conditions of superconducting proximity effect, we address the
correspondence between the common topological transition in infinite system and
the topological transition of other type that manifests itself in the positions
of the poles of the scattering matrices. We establish a universal dependence of
the pole positions in the vicinity of the common transition on the parameter
controlling the transition, and discuss the manifestations of the pole
transitions in the differential conductance.
