In a previous thread, I managed to get, via evidently now departed tashja, feedback from imo the brilliant theoretician Stanley Robertson re GR vs Yilmaz gravity theory: http://www.sciforums.com/threads/hawking-radiation.152642/page-20#post-3338529 Note particularly his reply paras 2 and 3 - emphasizing that logically redshift need be an exact exponential function of Newtonian gravitational potential. Well in his latest arXiv article, that logical proof is conveniently set out explicitly and simply in appendix A of: https://arxiv.org/abs/1606.01417# Most of you are so enthralled with the promotional hype glorifying 'infallible' Einstein this continuing centenary celebration year, mere contrary logical proofs will carry no weight. Still, one or two might recognize that just on it's own, appendix A (add appendix B for good measure) provides a death strike against 'perfect' GR. How long it takes for a general recognition of that will be more down to sociological/ideological forces than pure reason. In the end, that 2 + 2 = 4 must prevail. Will add that owing to GW self-consistency considerations, Carver Mead's G4v may prove to be a superior theory even to Yilmaz gravity. Currently corresponding with a few relevant parties on that one.