2025/07/22 by Jonah A. J. Duncan, Duncan, Jonah A. J., Luc Nguyen +1 · 2 citations
Mathematics · #Analysis of PDEs (math.AP) #Differential Geometry (math.DG) #FOS: Mathematics #Geometric Analysis and Curvature Flows #Navier-Stokes equation solutions #Nonlinear Partial Differential Equations
paper · pdf · doi:10.48550/arxiv.2507.16383
openalex publication_date 2025/07/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper we give a complete classification of positive viscosity solutions w to conformally invariant equations of the form \begincases f(λ(-Aw)) = (1)/(2), λ(-Aw)∈Γamp; in ℝ+n \newline w = 0 amp; on ∂ℝ+n, \endcases where Aw is the Schouten tensor of the metric gw = w-2|dx|2, Γ⊂ℝn is a symmetric convex cone and f is an associated defining function satisfying standard assumptions. Solutions to \eqrefab yield metrics gw of negative curvature-type which are locally complete near ∂ℝ+n. In particular, when (f,Γ) = (σ1,Γ1+), \eqrefab is the Loewner-Nirenberg problem in the upper half-space. More precisely, let μΓ+ denote the unique constant satisfying (-μΓ+, 1,…,1)∈∂Γ. We show that when μΓ+ >1 (e.g. when Γ= Γk+ for k<(n)/(2)), the hyperbolic solution w(0)(x) := xn is the unique solution to \eqrefab. More surprisingly, we show that when μΓ+ ≤ 1 (e.g. when Γ= Γk+ for k≥ (n)/(2)), the solution set consists of a monotonically increasing one-parameter family \w(a)(xn)\a≥ 0, of which the hyperbolic solution w(0) is the minimal solution. In either case, solutions of \eqrefab are functions of xn. Our proof involves a novel application of the method of moving spheres for which we must establish new estimates and regularity near ∂ℝ+n, followed by a delicate ODE analysis. As an application, we give counterexamples to local boundary C0 estimates on solutions to the fully nonlinear Loewner-Nirenberg problem when μΓ+ ≤ 1.