We consider the Klein-Gordon equation on Minkowski space with a spatial potential that decays as |x|^{-1} at infinity.
Building on previous work of Vasy for many-body scattering, we show that the Klein-Gordon operator admits a description as a non-elliptic Fredholm operator as a map between anisotropic Sobolev spaces.
The talk is based on ongoing joint work with Dean Baskin and Jesse Gell-Redman