The moving plane method and the uniqueness of high order elliptic equation with GJMS operator

In this paper, we study the following high order elliptic equation involving the GJMS operator: \begin{align*} \alpha P_{\mathbb{S}^n}v_{\alpha}+2Q_{g_{\mathbb{S}^n}}=2Q_{g_{\mathbb{S}^n}}e^{nv_{\alpha}}. \end{align*} We establish that if $\alpha>1$ and $n\geq3$, or if $\alpha\in (1-\epsilon_0, 1)$ with $n=2m\geq4$, then $v_{\alpha}\equiv0$. As an application, we present a new proof of the classical Beckner inequality.