CR Yamabe Equation on the Heisenberg Group via the method of moving spheres
Congwen Liu
TL;DR
The paper resolves the global Liouville classification for positive solutions of the CR Yamabe equation on the Heisenberg group by extending the method of moving spheres to the CR setting. It introduces a CR-adapted inversion framework, establishes Li–Nirenberg–Zhu type calculus lemmas in $\mathbb{H}^n$, and proves a Terracini-type integral inequality to replace the maximum principle. These tools yield that every positive solution must be a Jerison–Lee bubble, with explicit bubble parameters, removing prior finite-energy or symmetry restrictions. The results provide a complete three- to five-sentence overview of the CR Yamabe problem on $\mathbb{H}^n$ and its sharp extremals, mirroring classical Euclidean Yamabe theory in a noncommutative, sub-Riemannian context.
Abstract
In this paper, we classify positive solutions to the CR Yamabe equation on the Heisenberg group $\mathbb{H}^n$. We show that all such solutions are Jerison-Lee bubbles, without imposing any finite-energy or a priori symmetry assumptions. This result can be regarded as an analogue for $\mathbb{H}^n$ of the celebrated Caffarelli-Gidas-Spruck classification theorem in $\mathbb{R}^n$. To establish this, we develop a systematic approach to implement the method of moving spheres in the setting of the Heisenberg group.
