A connection between minimal surfaces and the two-dimensional analogues of a problem of Euler

If α\in\r, an $\alpha$-stationary surface in Euclidean space is a surface $\mathrm{\Sigma }$ whose mean curvature $H$ satisfies $H(p)=\alpha \mathrm{\mid }p{\mathrm{\mid }}^{-2}⟨\nu ,p⟩$, $p\in \mathrm{\Sigma }$. These surfaces generalize in dimension two a classical family of curves studied by Euler which are critical points of the moment of inertia of planar curves. In this paper we establish, via inversions, a one-to-one correspondence between $\alpha$-stationary surfaces and $-(\alpha +4)$-stationary surfaces. In particular, there is a correspondence between $-4$-stationary surfaces and minimal surfaces. Using this duality we give some results of uniqueness of $-4$-stationary surfaces and we solve the Börling problem.