Uniqueness of positive solutions to elliptic equations with the critical exponential growth on the unit disc and its applications

TL;DR

This paper proves the uniqueness of positive solutions to a class of elliptic equations with critical exponential growth on the unit disk, and applies this to problems in Trudinger-Moser inequalities and hyperbolic spaces.

Contribution

It establishes the first uniqueness result for positive solutions to exponential growth elliptic equations on the unit disk, and introduces a new approach for quantization and non-existence results.

Findings

Proves uniqueness of positive solutions for the specified elliptic equation.

Develops a new method for quantization and non-existence without blow-up analysis.

Extends the approach to hyperbolic spaces and high-dimensional Euclidean spaces.

Abstract

In this paper, we will solve this uniqueness problem of positive solutions to the following equations of exponential growth: \begin{equation*} \begin{cases} -\Delta u =\lambda ue^{u^2},\quad\quad & x\in B_1\subset \mathbb{R}^2,\\ u>0, & x\in B_1,\ \\ u=0,\quad\quad &x\in \partial B_1, \end{cases} \end{equation*} where $ 0<\lambda<\lambda_1(B_1)$ and $\lambda_1(B_1)$ denotes the first eigenvalue of the operator $-\Delta$ with the Dirichlet boundary in unit disk. Our method relies on delicate and difficult analysis of radial solutions to the above equation and careful asymptotic expansion of solutions near the boundary. This uniqueness result will shed some light on solving the conjecture that maximizers of the Trudinger-Moser inequality on the unit disc are unique. Furthermore, based on this uniqueness result, we develop a new strategy to establish the quantization property of elliptic equations with the critical exponential growth in the balls of hyperbolic spaces, and obtain the multiplicity and non-existence of positive critical points for super-critical Trudinger-Moser functional. Our method for the quantization property and non-existence of the critical points avoids using the complicated blow-up analysis used in the literature. This method can also be applied to study the similar problems in balls of high dimensional Euclidean space $\mathbb{R}^n$ or hyperbolic spaces provided the uniqueness for the corresponding quasilinear elliptic equations with the critical exponential growth is established.