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Mar4-12, 08:42 AM
Sci Advisor
P: 5,464
The FRW metric can definitly not be derived using flat space + perturbative strings; I don't know which realistic vacuum solutions have been constructed so far, but AdS is not the right way to go b/c AdS is not realistic; with a positive cosmological constant one needs dS instead, for FRW w/o cc again something different.