Gauge/Gravity correspondence, string theory or any QG?

[ShayanJ]

In this note, the author says:

The AdS/CFT correspondence is the an exact relationship between any theory of quantum gravity in asymptotically $AdS_{d+1}$ spacetime and an ordinary $CFT_d$ ,without gravity.

with the following footnote:

Some people might obect to the word ‘any’ here. To be safe, we could say ‘any theory that we
know how to define in the UV and acts like ordinary gravity+QFT in the IR.’

But I don't understand how that can be true. All the evidence for the cojecture arises from string theory: Similarity of Large N expansion and the perturbative expansion of a string theory and the equivalent low energy description of N coinciding branes in terms of SUGRA and $\mathcal N=4$ SYM(which are both low energy limits of a string theory).

So, how can the author claim that this correspondence is between any theory of QG and a CFT?

Thanks

 

[haushofer]

I think he can't. It's a matter of intuïtion how general holography could be, but intuïtion is no hard proof. I have the same feelings with flat space holography or non-relativistic AdS/CFT. Without an explicit embedding in string theory (or another theory of QG, as the author suggests) one should be very carefull.

But maybe there is some Wilsonian argument or something which makes his claim possible. I'd be happy to see that too :)