2 problems

Let $D$ be a bounded domain in $\mathbb{R}^2$. Let $A_x(r_1,r_2)$ be an admissible annular domain centred at $x$, with $r_2>r_1>0$, and let $B_{r_2}(x)$ be admissible. Denote by…

Let $D \subset \mathbb{R}^m$, with $m \geqslant 2$, be a bounded domain with sufficiently smooth boundary, and let $r>0$ satisfy $|B_r|=|D|$. A function $u$ is panharmonic if it be…