Global weak solutions for the inverse mean curvature flow in the Heisenberg group
Adriano Pisante, Eugenio Vecchi
TL;DR
The paper develops a rigorous weak formulation for inverse mean curvature flow in the Heisenberg group, using Riemannian approximations $d_ε$ and a $p$-Laplace regularization that connects IMCF to $p$-harmonic potentials. It establishes uniform gradient bounds and two-sided asymptotics for $p$-capacitary potentials, proves a Bochner-type inequality for the energy density, and constructs barrier-based boundary estimates that extend to the exterior domain, culminating in the existence of global weak IMCF level-sets that grow at an explicit rate dictated by Korányi geometry. The core contributions include a Cheng–Yau-type interior gradient bound, boundary gradient control, and a limiting framework that yields proper, Lipschitz weak solutions $u^ε$ whose level sets $\{u^ε=s\}$ behave like expanding Korányi spheres as time progresses. This work lays foundational steps toward a full understanding of IMCF in sub-Riemannian settings, with implications for geometric analysis on Carnot groups and asymptotic geometric behavior at infinity.
Abstract
We consider the inverse mean curvature flow (IMCF) in the Heisenberg group $(\He^n, d_\varepsilon)$, where $d_\varepsilon$ is distance associated to either $| \cdot |_\varepsilon$, $\varepsilon>0$, the natural family of left-invariant Riemannian metrics, or with their sub-Riemannian counterparts for $\varepsilon=0$. For $Ω\subseteq \He^n$ an open set with smooth boundary $Σ_0=\partial Ω$ satisfying a uniform exterior gauge-ball condition and bounded complement we show existence of a global weak IMCF of generalized hypersurfaces $\{Σ^\varepsilon_s\}_{s \geq 0} \subseteq \mathbb{H}^n$ which are level sets of a proper globally Lipschitz function with logarithmic growth at infinity. Here, both in the Riemannian and in the sub-Riemannian setting, we adopt the weak formulation introduced by Huisken and Ilmanen in \cite{HuiskenIlmanen}, following the approach in \cite{Moser} due to Moser and based on the the link between IMCF and $p$-harmonic functions.
