Some isoperimetric inequalities in the plane with radial power weights

Abstract

We consider the punctured plane with volume density $|x|^\alpha$ and perimeter density $|x|^\beta$. We show that centred balls are uniquely isoperimetric for indices $(\alpha,\beta)$ which satisfy the conditions $\alpha-\beta+1>0$, $\alpha\leq 2\beta$ and $\alpha(\beta+1)\leq\beta^2$ except in the case $\alpha=\beta=0$ which corresponds to the classical isoperimetric inequality.