Upper and lower bounds for the first Robin eigenvalue of nonlinear elliptic operators
Rosa Barbato, Francesco Della Pietra
TL;DR
The paper addresses the problem of bounding the first Robin eigenvalue $\lambda_p(\beta,\Omega)$ of the nonlinear $p$-Laplacian under Robin boundary conditions. It develops a Thompson-type variational framework and analyzes asymptotics as $\beta$ varies, yielding explicit upper bounds in terms of the Dirichlet eigenvalue and the $p$-torsional rigidity, as well as a general lower bound via a convexity argument. The results extend classical bounds for the Laplacian (e.g., Sperb, Pólya) to the nonlinear setting and connect spectral data to geometric quantities like $P(\Omega)$ and $T_p(\Omega)$. Overall, the work provides practical estimates for $\lambda_p(\beta,\Omega)$ and establishes structural links between Robin, Dirichlet, and Neumann-type problems through variational principles and limit analyses.
Abstract
Let $Ω$ be a bounded, smooth domain of $\mathbb R^N$, $N\ge 2$. In this paper, we prove some inequalities involving the first Robin eigenvalue of the $p$-laplacian operator. In particular, we prove an upper bound for the first Robin eigenvalue of nonlinear elliptic operators in terms of the first Dirichlet eigenvalue.
