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Related papers: Wolf-Keller theorem for Neumann eigenvalues

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This paper studies the optimization of the lowest eigenvalue of the magnetic Steklov problem on planar domains. In the bounded domain setting and for magnetic fields of moderate strengths, we prove that among all simply-connected smooth…

Analysis of PDEs · Mathematics 2026-02-20 Ayman Kachmar , Vladimir Lotoreichik

In this paper we prove a sharp inequality of Szeg\H{o}-Weinberger type for the first nontrivial eigenvalue of the $p-$Laplacian with Neumann boundary conditions. This applies to convex sets with given diameter. Some variants, extensions and…

Analysis of PDEs · Mathematics 2015-09-01 L. Brasco , C. Nitsch , C. Trombetti

The second eigenvalue of the Robin Laplacian is shown to be maximal for the ball among domains of fixed volume, for negative values of the Robin parameter $\alpha$ in the regime connecting the first nontrivial Neumann and Steklov…

Spectral Theory · Mathematics 2018-10-18 Pedro Freitas , Richard Laugesen

We consider three different questions related to the Steklov and mixed Steklov problems on surfaces. These questions are connected by the techniques that we use to study them, which exploit symmetry in various ways even though the surfaces…

Inside a fixed bounded domain $\Omega$ of the plane, we look for the best compact connected set $K$, of given perimeter, in order to maximize the first Dirichlet eigenvalue $\lambda_1(\Omega\setminus K)$. We discuss some of the qualitative…

Analysis of PDEs · Mathematics 2018-03-28 Antoine Henrot , Davide Zucco

We prove the Pleijel theorem in non-collapsed RCD spaces, providing an asymptotic upper bound on the number of nodal domains of Laplacian eigenfunctions. As a consequence, we obtain that the Courant nodal domain theorem holds except at most…

Spectral Theory · Mathematics 2023-09-27 Nicolò De Ponti , Sara Farinelli , Ivan Yuri Violo

We prove the existence of an open set $\Omega\subset\mathbb{S}^2$ for which the first positive eigenvalue of the Laplacian with Neumann boundary condition exceeds that of the geodesic disk having the same area. This example holds for large…

Analysis of PDEs · Mathematics 2025-03-31 Dorin Bucur , Richard S. Laugesen , Eloi Martinet , Mickaël Nahon

In this paper we prove that given a volume, among all domains with smooth boundary in rank-1 symmetric spaces of noncompact type, geodesic balls maximizes the first nonzero Steklov eigenvalue. We also prove a comparison result for the first…

Differential Geometry · Mathematics 2012-08-09 Binoy , G. Santhanam

We prove two bounds for the first Robin eigenvalue of the Finsler Laplacian with negative boundary parameter in the planar case. In the constant area problem, we show that the Wulff shape is the maximizer only for values which are close to…

Analysis of PDEs · Mathematics 2018-11-09 Gloria Paoli , Leonardo Trani

We introduce an analogue of Payne's nodal line conjecture, which asserts that the nodal (zero) set of any eigenfunction associated with the second eigenvalue of the Dirichlet Laplacian on a bounded planar domain should reach the boundary of…

Analysis of PDEs · Mathematics 2017-07-03 J. B. Kennedy

Inspired by a recent result of Funano's, we provide a sharp quantitative comparison result between the first nontrivial eigenvalues of the Neumann Laplacian on bounded convex domains $\Omega_{1} \subset \Omega_{2}$ in any dimension $d$…

Spectral Theory · Mathematics 2025-06-10 Pedro Freitas , James B. Kennedy

In this paper we prove that among all convex domains of the plane with two axis of symmetry, the maximizer of the first non trivial Neumann eigenvalue $\mu_1$ with perimeter constraint is achieved by the square and the equilateral triangle.…

Analysis of PDEs · Mathematics 2022-11-01 Antoine Henrot , Antoine Lemenant , Ilaria Lucardesi

An isoperimetric inequality for lower order nonzero Neumann eigenvalues of the Witten-Laplacian on bounded domains in a Euclidean space or a hyperbolic space has been proven in this paper. About this conclusion, we would like to point out…

Analysis of PDEs · Mathematics 2025-06-13 Ruifeng Chen , Jing Mao

In 1996 Erdoes showed that among planar domains of fixed area, the smallest principal eigenvalue of the Dirichlet Laplacian with a constant magnetic field is uniquely achieved on the disk. We establish a quantitative version of this…

Spectral Theory · Mathematics 2023-05-15 Rohan Ghanta , Lukas Junge , Leo Morin

We consider the magnetic Laplacian with the homogeneous magnetic field in two and three dimensions. We prove that the $(k+1)$-th magnetic Neumann eigenvalue of a bounded convex planar domain is not larger than its $k$-th magnetic Dirichlet…

Spectral Theory · Mathematics 2024-05-21 Vladimir Lotoreichik

We provide isoperimetric Szeg\"{o}-Weinberger type inequalities for the first nontrivial Neumann eigenvalue $\mu_{1}(\Omega)$ in Gauss space, where $\Omega$ is a possibly unbounded domain of $\mathbb{R}^{N}$. Our main result consists in…

Analysis of PDEs · Mathematics 2011-10-19 Francesco Chiacchio , Giuseppina di Blasio

In arXiv:1305.5193v1, the authors have shown that Putnam's inequality for the norm of self-commutators can be improved by a factor of $\frac{1}{2}$ for Toeplitz operators with analytic symbol $\varphi$ acting on the Bergman space…

Functional Analysis · Mathematics 2013-11-11 Matthew Fleeman , Dmitry Khavinson

We consider the Dirichlet and Neumann eigenvalues of the Laplacian for a planar, simply connected domain. The eigenvalues admit a characterization in terms of a layer potential of the Helmholtz equation. Using the exterior conformal mapping…

Numerical Analysis · Mathematics 2024-10-22 Marius Beceanu , Jiho Hong , Hyun-Kyoung Kwon , Mikyoung Lim

We show that as the ratio between the first Dirichlet eigenvalues of a convex domain and of the ball with the same volume becomes large, the same must happen to the corresponding ratio of isoperimetric constants. The proof is based on the…

Spectral Theory · Mathematics 2008-06-10 Pedro Freitas , David Krejcirik

We prove a sharp isoperimetric inequality for the harmonic mean of the first $m-1$ nonzero Neumann eigenvalues for bounded Lipschitz domains symmetric about the origin in Gauss space. Our result generalizes the Szeg\"o-Weinberger type…

Spectral Theory · Mathematics 2026-01-23 Yi Gao , Kui Wang