  The Langevin equation for the pair contact process with diffusion (PCPD)
2A->3A, 2A->0 can be mapped by a Cole-Hopf transformation to a
Kardar-Parisi-Zhang equation in a potential which has been discussed previously
in the context of non-equilibrium wetting. Using this transformation the phase
transition in the PCPD manifests itself as a depinning transition at the
borderline of a region of phase coexistence, supporting the conjecture that the
PCPD belongs to the DP universality class.
