p-capacity vs surface-area

TL;DR

This paper establishes new bounds relating p-capacity and surface area of convex sets in , extending classical inequalities and providing insights into the geometric properties influencing electrostatic capacity.

Contribution

It introduces novel inequalities connecting p-capacity, surface area, and mean curvature, extending the Plya-Szego inequality to a broader class of convex sets.

Findings

Derived bounds for p-capacity in terms of surface area and mean curvature.

Extended the Plya-Szego inequality to convex sets in .

Identified constants close to the conjectured optimal values by Plya-Szego.

Abstract

This paper is devoted to exploring the relationship between the $[1,n)\ni p$-capacity and the surface-area in $\mathbb R^{n\ge 2}$ which especially shows: if $\Omega\subset\mathbb R^n$ is a convex, compact, smooth set with its interior $\Omega^\circ\not=\emptyset$ and the mean curvature $H(\partial\Omega,\cdot)>0$ of its boundary $\partial\Omega$ then $$ \left(\frac{n(p-1)}{p(n-1)}\right)^{p-1}\le\frac{\left(\frac{\hbox{cap}_p(\Omega)}{\big(\frac{p-1}{n-p}\big)^{1-p}\sigma_{n-1}}\right)}{\left(\frac{\hbox{area}(\partial\Omega)}{\sigma_{n-1}}\right)^\frac{n-p}{n-1}}\le\left(\sqrt[n-1]{\int_{\partial\Omega}\big(H(\partial\Omega,\cdot)\big)^{n-1}\frac{d\sigma(\cdot)}{\sigma_{n-1}}}\right)^{p-1}\quad\forall\quad p\in (1,n) $$ whose limits $1\leftarrow p\ \&\ p\rightarrow n$ imply $$ 1=\frac{cap_1(\Omega)}{\hbox{area}(\partial\Omega)}\ \ \& \ \int_{\partial\Omega}\big(H(\partial\Omega,\cdot)\big)^{n-1}\frac{d\sigma(\cdot)}{\sigma_{n-1}}\ge 1, $$ thereby not only discovering that the new best known constant is roughly half as far from the one conjectured by P\'olya-Szeg\"o in \cite[(2)]{P} but also extending the P\'olya-Szeg\"o inequality in \cite[(5)]{P}, with both the conjecture and the inequality being stated for the electrostatic capacity of a convex solid in $\mathbb R^3$.