Sharp Boundary Growth Rate Estimate of the Singular Equation $-Δu=u^{-γ}$ in a Critical Cone

Fuente: arXiv
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Main Authors: Wu, Leyun, Zhang, Chilin
Format: Preprint
Published: 2025
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_version_ 1866911069782409216
author Wu, Leyun
Zhang, Chilin
author_facet Wu, Leyun
Zhang, Chilin
contents For $γ>0$, we study the sharp boundary growth rate estimate of solutions to the Dirichlet problem of the singular Lane-Emden-Fowler equation \begin{equation*} -Δu=u^{-γ} \end{equation*} in a critical $C^{1,1}$ epigraphical cone $Cone_Σ$. We show that the growth rate estimate exhibits fundamentally different behaviors in the following three cases: $1<γ<2$, $γ=2$, and $γ>2$. Moreover, we obtain the sharp growth rate estimate near the origin for $γ>1$. As a consequence, we show that when $Cone_Σ$ is a $C^{1,1}$ epigraphical cone, the additional solvability condition in \cite[Theorem 1.3]{GuLiZh25} is both sufficient and necessary to achieve the growth rate therein, thereby resolving the main open question left in that paper. With the growth rate estimate, we also derive the optimal modulus of continuity for solutions via the interior Schauder estimate. Our approach is to control the values of a solution $U(x)$ in the region $Ω=Cone_Σ\cap B_{1}$ by introducing a sequence of reference points $p_{k}=\frac{16^{1-k}}{2}\vec{e_{n}}$. From the Green function representation of $U(x)$, we derive a discrete integral equation for the sequence $a_{k}=16^{kϕ}U(p_{k})$. Such a computation converts the original PDE problem into a recursion for a discrete integral equation, which can be effectively analyzed using basic ODE methods.
format Preprint
id arxiv_https___arxiv_org_abs_2507_16319
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sharp Boundary Growth Rate Estimate of the Singular Equation $-Δu=u^{-γ}$ in a Critical Cone
Wu, Leyun
Zhang, Chilin
Analysis of PDEs
35B40, 35J75, 45G05
For $γ>0$, we study the sharp boundary growth rate estimate of solutions to the Dirichlet problem of the singular Lane-Emden-Fowler equation \begin{equation*} -Δu=u^{-γ} \end{equation*} in a critical $C^{1,1}$ epigraphical cone $Cone_Σ$. We show that the growth rate estimate exhibits fundamentally different behaviors in the following three cases: $1<γ<2$, $γ=2$, and $γ>2$. Moreover, we obtain the sharp growth rate estimate near the origin for $γ>1$. As a consequence, we show that when $Cone_Σ$ is a $C^{1,1}$ epigraphical cone, the additional solvability condition in \cite[Theorem 1.3]{GuLiZh25} is both sufficient and necessary to achieve the growth rate therein, thereby resolving the main open question left in that paper. With the growth rate estimate, we also derive the optimal modulus of continuity for solutions via the interior Schauder estimate. Our approach is to control the values of a solution $U(x)$ in the region $Ω=Cone_Σ\cap B_{1}$ by introducing a sequence of reference points $p_{k}=\frac{16^{1-k}}{2}\vec{e_{n}}$. From the Green function representation of $U(x)$, we derive a discrete integral equation for the sequence $a_{k}=16^{kϕ}U(p_{k})$. Such a computation converts the original PDE problem into a recursion for a discrete integral equation, which can be effectively analyzed using basic ODE methods.
title Sharp Boundary Growth Rate Estimate of the Singular Equation $-Δu=u^{-γ}$ in a Critical Cone
topic Analysis of PDEs
35B40, 35J75, 45G05
url https://arxiv.org/abs/2507.16319