A Liouville theorem for CR Yamabe type equation on Sasakian manifolds
Biqiang Zhao
TL;DR
This work proves Liouville-type rigidity theorems for a CR Yamabe-type semilinear equation on complete noncompact Sasakian manifolds with nonnegative pseudo-Hermitian Ricci curvature. Using Jerison–Lee's differential identity together with refined integral estimates for an energy-like quantity $\mathcal{M}$ and a subcritical nonlinearity, it is shown that $\mathcal{M}=0$, which forces $H'(f)=2H(f)$ and hence $F(u)=C u^{1+\frac{2}{n}}$. Consequently, the manifold must be CR isometric to the Heisenberg group $\mathbb{H}^n$ and the positive solution $u$ takes the Jerison–Lee model form; results are established for $n=1$, $n=2$, and $n\ge 3$ under appropriate volume-growth conditions. This delivers a unifying rigidity framework across dimensions in the Sasakian setting with nonnegative curvature.
Abstract
In this paper, we study the CR Yamabe type equation \begin{align} Δ_b u+F(u)=0 \nonumber \end{align} on complete noncompact $(2n+1)$-dimensional Sasakian manifolds with nonnegative curvature. Under some assumptions, we prove a rigidity result, that is, the manifold is CR isometric to Heisenberg group $\mathbb{H}^n$. The proofs are based on the Jerison-Lee's differential identity combining with integral estimates.
