Swing amplification and global modes reciprocity in models with cusps
  Using 3D N-body simulations we analyse an onset of the bar in cuspy models,
and argue that role of swing amplification is twofold. Amplified shot noise due
to disc discreteness hampers bar formation, while induced resonance
perturbations allow bar amplitude to overcome shots. A bar pattern speed and a
growth rate obtained in N-body simulations agree well with global mode
analysis.
