Continuum limit of hypergraph $p$-Laplacian equations on point clouds
Kehan Shi
TL;DR
The paper analyzes the continuum limit of hypergraph $p$-Laplacian equations on point clouds in a semi-supervised learning setting. It establishes that the discrete hypergraph operator $L^{H_n}_{p,\varepsilon_n}$ is consistent with a nonlocal $p$-Laplacian and, under suitable scaling $\varepsilon_n$ and density assumptions, the solutions converge uniformly (almost surely) to the viscosity solution of the weighted $p$-Laplacian $\Delta^\rho_p u=0$ in $\Omega\setminus\mathcal{O}$ with Dirichlet data on $\mathcal{O}$ and Neumann data on $\partial\Omega$. The key contributions include a pointwise consistency analysis connecting the discrete operator to a continuum $L_p$ in the interior and near the boundary, a Hölder regularity estimate for discrete solutions, and a full discrete-to-continuum convergence result in the viscosity framework, justifying the hypergraph discretization as a faithful representation of the continuum problem on point clouds. These results provide theoretical grounding for hypergraph-based discretizations of the $p$-Laplacian in semi-supervised learning tasks on high-dimensional data geometries.
Abstract
This paper studies a class of $p$-Laplacian equations on point clouds that arise from hypergraph learning in a semi-supervised setting. Under the assumption that the point clouds consist of independent random samples drawn from a bounded domain $Ω\subset\mathbb{R}^d$, we investigate the asymptotic behavior of the solutions as the number of data points tends to infinity, with the number of labeled points remains fixed. We show, for any $p>d$ in the viscosity solution framework, that the continuum limit is a weighted $p$-Laplacian equation subject to mixed Dirichlet and Neumann boundary conditions. The result provides a new discretization of the $p$-Laplacian on point clouds.
