The Minimal Gap Between Λ_(2)(Ω) and Λ_(¥)(Ω) in a Class of Convex Domains

We consider the minimization problem \begin{eqnarray*} \min_{\Omega\in X}\left(\Lambda_2-\Lambda_\infty\right)(\Omega), \end{eqnarray*} where $\Lambda_2(\Omega)$\ and $\Lambda_\infty(\Omega)$\ are the (square root of the) first eigenvalue of the Laplacian and the first eigenvalue of the $\infty-$Laplacian respectively. $X$ is the class of convex domains with prescribed diameter. We prove existence of a solution, and we provide several geometrical properties of minimizers