A part of AdS/CFT that works exactly, no approximations needed?

Standard AdS/CFT only works cleanly in limiting regimes — large N, strong coupling, heavy operators. By placing a CFT on an open solid torus in a specific Weyl frame, this paper identifies a purely kinematic sector where the holographic dictionary is exact and finite, no approximations required. The AdS geometry here is a geometric bookkeeping device, not a dynamical spacetime. As a concrete payoff, the framework gives a replica-free derivation of entanglement entropy from two-point functions — a result that usually requires a cumbersome analytic continuation trick.