Vanishing of the Fefferman-Graham obstruction tensor was proposed by Anderson and Chrusciel as a tool for studying asymptotically simple solutions to Einstein's equations. It is a conformally covariant equation and a stronger condition: every lambda-vacuum solution in any even dimension has vanishing Fefferman-Graham tensor. The equation is an alternative for known Friedrich's construction of conformal version of Einstein's equations. This approach will work if one can show that the equation is hyperbolic. I will discuss the proof in my talk.
