Grav. + GUT (Gravity from a Particle Physicist's perspective)

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Ha, ha, I don't know what to call it. Minimalist seems fine with me. I guess Meissner and Nicolai are really saying, well, we don't need a theory of gravity until the Planck scale. At that scale, maybe it's string theory or something. So we present a theory which is consistent with those (hopefully), but which is as minimalist as possible until then.

My grouping:

1) UV gravity requires new degrees of freedom

- string theory, which subdivides based on low energy proposals
--- GUT inspired F-theory (Vafa et al, Wijnholt et al)
--- No GUT (Meissner and Nicolai)

- others which don't work (yet?) but are terribly cute (Volovik, Wen, Horava; also it's too early to say, but I hope GFT will fall here)

2) UV gravity does not require new degrees of freedom, ie. Asymptotic Safety. Here to make predictions, maybe we need a definite theory of matter, so the subclassification depends on the theory of matter

- matter is asymptotically free, and matter degrees of freedom beyond the SM are needed (Percacci)

- matter is asymptotically safe, but not necessarily asymptotically free, and matter degrees of freedom beyond the SM ar not needed (not sure about this, but I think I'd put Shaposhnikov and Wetterich here, also Scherer et al)

- matter is asymptotically free, and matter degrees of freedom beyond the SM are not needed (ruled out by Landau poles)

- matter is asymptotically safe, but not necessarily asymptotically free, and matter degress of freedom beyond the SM are needed (Percacci's Asymptotic Safety landscape nightmare)

- no definite theory of matter needed, generic (universal?) asymptotic safety of gravity effects (again not sure about this, but I think I'd put Weinberg here, also Niedermaier and Reuter's Living Reviews perspective)