Role of -ghost in classical SUGRA
We conclude that the -ghost, more precisely , is important in classical SUGRA:
  • it removes the nonphysical states

  • it explains the consistency of the SUGRA constraints at the nonlinear level

However, the -ghost is nonpolynomial. It would be fair to say that it is not sufficiently well understood.

  • an elementary argument for the consistency of the nonlinear theory might shed some light on the -ghost

(However, I do not know such argument)