Gradient estimates for the insulated conductivity problem: the case of $m$-convex inclusions

TL;DR

This paper derives precise gradient blow-up estimates for an insulated conductivity problem involving $m$-convex inclusions in higher dimensions, revealing the blow-up rate as the inclusions approach each other.

Contribution

It establishes the pointwise gradient estimates and the blow-up rate for $m$-convex inclusions, demonstrating optimality in certain symmetric cases.

Findings

Gradient blow-up rate of order $ ext{} extstylerac{1}{m}+eta$ as $ ext{} extstylerac{1}{ ext{} ext{distance}}$ tends to zero.

Optimality of the blow-up rate for axisymmetric $m$-convex inclusions.

Explicit expression for the blow-up exponent $eta$ depending on $d$ and $m$.

Abstract

We consider an insulated conductivity model with two neighboring inclusions of $m$-convex shapes in $\mathbb{R}^{d}$ when $m\geq2$ and $d\geq3$. We establish the pointwise gradient estimates for the insulated conductivity problem and capture the gradient blow-up rate of order $\varepsilon^{-1/m+\beta}$ with $\beta=[-(d+m-3)+\sqrt{(d+m-3)^{2}+4(d-2)}]/(2m)\in(0,1/m)$, as the distance $\varepsilon$ between these two insulators tends to zero. In particular, the optimality of the blow-up rate is also demonstrated for a class of axisymmetric $m$-convex inclusions.