Stability of $L^p$ Dirichlet solvability under small bi-Lipschitz transformations of domains
Joseph Feneuil, Linhan Li, Jinping Zhuge
TL;DR
This work proves that the solvability of the L^p Dirichlet problem for the Laplacian on a Lipschitz domain is stable under small bi-Lipschitz deformations, preserving the same p in (1,∞). The authors introduce a novel Green-function–based change of variables that encodes perturbations in a non-flat base domain, and they construct an intermediate operator whose Carleson-perturbation controls transfer of solvability to the perturbed domain. By combining Carleson perturbation stability with bi-Lipschitz invariance, they establish (D)_p for all p>1 on small perturbations of convex domains and, more generally, on strongly quasiconvex domains. The results unify convex and C^1-type settings and extend stability to perturbations not limited to the transversal direction, with potential applicability to broader elliptic operators and Neumann problems.
Abstract
We show that small bi-Lipschitz deformations of a Lipschitz domain (with possibly large Lipschitz constant) preserve the solvability of the Dirichlet problem for the Laplacian with boundary data in $L^p$, for the same value of $p>1$. As a consequence, for all $p\in(1,\infty)$, we obtain the solvability of the $L^p$ Dirichlet problem for small Lipschitz perturbations of convex domains, thereby unifying two fundamentally different settings in which such results were previously known: convex and $C^1$ domains. The key ingredient and novelty of our approach is a construction of a change of variables based on a non-constant basis derived from the Green function, which encodes the geometry of the base domain.
