2 problems

Let $\hat{G}\subset\widehat{\operatorname{Diff}}(\mathbb{R}^{n}_{0})$ be a subgroup of formal diffeomorphisms. Realisation conjecture. There exists a smooth realisation…

Zhang's conjecture. The diffeomorphism $\varphi$ is not embedded in a $C^{\infty}$ (respectively, analytic) flow.