New symmetries in Fierz-Pauli massive gravity
  We expose a new symmetry for linear perturbations around a solution of
non-linear Fierz-Pauli massive gravity plus a bare cosmological constant. The
cosmological constant is chosen such that the background metric is flat while
the Stuckelberg fields have a non-trivial profile. Around this background, at
linear order the new symmetry reduces the propagating degrees of freedom to
those of General Relativity, namely the massless helicity 2 modes only. We
discuss the physical consequences and possible applications of these findings.
