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Bibliographic Details
Main Author: Weinkove, Ben
Format: Preprint
Published: 2021
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Online Access:https://arxiv.org/abs/2103.14143
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author Weinkove, Ben
author_facet Weinkove, Ben
contents We consider the insulated conductivity problem with two unit balls as insulating inclusions, a distance of order $\varepsilon$ apart. The solution $u$ represents the electric potential. In dimensions $n \ge 3$ it is an open problem to find the optimal bound on the gradient of $u$, the electric field, in the narrow region between the insulating bodies. Li-Yang recently proved a bound of order $\varepsilon^{-(1-γ)/2}$ for some $γ>0$. In this paper we use a direct maximum principle argument to sharpen the Li-Yang estimate for $n \ge 4$. Our method gives effective lower bounds on the best constant $γ$, which in particular approach $1$ as $n$ tends to infinity.
format Preprint
id arxiv_https___arxiv_org_abs_2103_14143
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle The insulated conductivity problem, effective gradient estimates and the maximum principle
Weinkove, Ben
Analysis of PDEs
We consider the insulated conductivity problem with two unit balls as insulating inclusions, a distance of order $\varepsilon$ apart. The solution $u$ represents the electric potential. In dimensions $n \ge 3$ it is an open problem to find the optimal bound on the gradient of $u$, the electric field, in the narrow region between the insulating bodies. Li-Yang recently proved a bound of order $\varepsilon^{-(1-γ)/2}$ for some $γ>0$. In this paper we use a direct maximum principle argument to sharpen the Li-Yang estimate for $n \ge 4$. Our method gives effective lower bounds on the best constant $γ$, which in particular approach $1$ as $n$ tends to infinity.
title The insulated conductivity problem, effective gradient estimates and the maximum principle
topic Analysis of PDEs
url https://arxiv.org/abs/2103.14143