Exact residual finiteness growth conjecture for torsion-free nilpotent groups

Let $G$ be a torsion-free nilpotent group, and let $\delta$ be the constant in the previously established upper bound for the residual finiteness growth $\operatorname{RF}_G$. Exact residual finiteness growth conjecture. For every torsion-free nilpotent group $G$ it holds that

$$\operatorname{RF}_G=\log^\delta.$$

The paper presents this as the conjecture that the cited upper bound is exact; the preceding theorem establishes the corresponding restricted growth function using normal subgroups containing $G^p$, but not the asserted equality for $\operatorname{RF}_G$ itself.