The asymptotic symmetry group of $AdS_{d+1}$ is $SO(d,2)$, which just so happens to be the conformal group of $d$-dimensional Minkowski spacetime. Therefore the boundary dual, if it exists, has conformal symmetry. This is the usual "first hint" towards AdS/CFT that one sees at the start of an introduction to the subject.
Does this conformal symmetry of the dual boundary theory get "enhanced" to the Weyl symmetry? It seems that in the literature, the boundary theory is assumed to have not only conformal symmetry but Weyl symmetry, at least up to an anomaly. But I don't see how to justify this based on symmetry considerations alone, since the Weyl group is much larger than $SO(d,2)$. Is there some subtle way to show that the boundary theory has Weyl symmetry?
