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We investigate the relationship between the Neumann and Steklov principal eigenvalues emerging from the study of collapsing convex domains in $\mathbb{R}^2$. Such a relationship allows us to give a partial proof of a conjecture concerning…

Analysis of PDEs · Mathematics 2025-03-04 Paolo Acampora , Vincenzo Amato , Emanuele Cristoforoni

We consider Steklov eigenvalues of nearly circular domains in $\R^{2}$ of fixed unitary area. In \cite{viator2018}, the authors treated such domains as perturbations of the disk, and they computed the first-order term of the asymptotic…

Analysis of PDEs · Mathematics 2025-05-01 Lucas Alland , Robert Viator

Let $\mathbb{M}$ denote a complete, simply connected Riemannian manifold with sectional curvature $K_{\mathbb{M}} \leq k$ and Ricci curvature $\text{Ric}_{\mathbb{M}} \geq (n-1)K$, where $k,K \in \mathbb{R}$. Then for a bounded domain…

Differential Geometry · Mathematics 2020-08-26 Sheela Verma

We consider weighted p-Laplace type equations with homogeneous Neumann boundary conditions in convex domains, where the weight is a log-concave function which may degenerate at the boundary. In the case of bounded domains, we provide sharp…

Analysis of PDEs · Mathematics 2025-01-14 Carlo Alberto Antonini , Giulio Ciraolo , Francesco Pagliarin

We show that the multiplicity of the second normalized adjacency matrix eigenvalue of any connected graph of maximum degree $\Delta$ is bounded by $O(n \Delta^{7/5}/\log^{1/5-o(1)}n)$ for any $\Delta$, and by…

Combinatorics · Mathematics 2023-06-19 Theo McKenzie , Peter M. R. Rasmussen , Nikhil Srivastava

Among all $C^{\infty}$ bounded domains with equal volume, we show that the second eigenvalue of the Robin plate is uniquely maximized by an open ball, so long as the Robin parameter lies within a particular range of negative values. Our…

Analysis of PDEs · Mathematics 2021-02-18 L. Mercredi Chasman , Jeffrey J. Langford

We build a one-parameter family of S^{1}-invariant metrics on the unit disc with fixed total area for which the second eigenvalue of the Laplace operator in the case of both Neumann and Dirichlet boundary conditions is simple and has an…

Spectral Theory · Mathematics 2007-05-23 P. Freitas

We consider a spinor domain wall embedded in a five-dimensional spacetime with a nondiagonal metric. The corresponding plane symmetric solutions for linear and nonlinear spinor fields with different parameters are obtained. It is shown that…

General Relativity and Quantum Cosmology · Physics 2023-07-31 Vladimir Dzhunushaliev , Vladimir Folomeev , Dina Zholdakhmet

We study the minimization of the positive principal eigenvalue associated to a weighted Neumann problem settled in a bounded smooth domain $\Omega\subset \mathbb{R}^{N}$, within a suitable class of sign-changing weights. Denoting with $u$…

Analysis of PDEs · Mathematics 2021-11-03 Dario Mazzoleni , Benedetta Pellacci , Gianmaria Verzini

Neumann eigenvalues being non-decreasing with respect to domain inclusion, it makes sense to study the two shape optimization problems $\min\{\mu_k(\Omega):\Omega \mbox{ convex},\Omega \subset D, \}$ (for a given box $D$) and…

Let $x:M\to\mathbb{S}^{n+1}(1)$ be an n-dimensional compact hypersurface with constant scalar curvature $n(n-1)r,~r\geq 1$, in a unit sphere $\mathbb{S}^{n+1}(1),~n\geq 5$. We know that such hypersurfaces can be characterized as critical…

Differential Geometry · Mathematics 2010-10-20 Haizhong Li , Xianfeng Wang

The sum of the first n energy levels of the planar Laplacian with constant magnetic field of given total flux is shown to be maximal among triangles for the equilateral triangle, under normalization of the ratio (moment of inertia)/(area)^3…

Analysis of PDEs · Mathematics 2015-05-27 Richard S. Laugesen , Jian Liang , Arindam Roy

We prove that in Riemannian manifolds the $k$-th Steklov eigenvalue on a domain and the square root of the $k$-th Laplacian eigenvalue on its boundary can be mutually controlled in terms of the maximum principal curvature of the boundary…

Differential Geometry · Mathematics 2018-10-04 Changwei Xiong

We prove a Payne-Weinberger type inequality for the $p$-Laplacian Neumann eigenvalues ($p\ge 2$). The inequality provides the sharp upper bound on convex domains, in terms of the diameter alone, of the best constants in Poincar\'e…

Analysis of PDEs · Mathematics 2011-10-14 L. Esposito , C. Nitsch , C. Trombetti

In this paper, we prove a sharp lower bound of the first (nonzero) eigenvalue of Finsler-Laplacian with the Neumann boundary condition. Equivalently, we prove an optimal anisotropic Poincar\'e inequality for convex domains, which…

Analysis of PDEs · Mathematics 2017-05-30 Guofang Wang , Chao Xia

We consider the Dirichlet Laplacian with a constant magnetic field in a two-dimensional domain of finite measure. We determine the sharp constants in semi-classical eigenvalue estimates and show, in particular, that Polya's conjecture is…

Mathematical Physics · Physics 2007-10-05 Rupert L. Frank , Michael Loss , Timo Weidl

Refining the sharp upper bounds $\mu_{k,d}^* $ obtained by Kr\"oger (1999) for the $k$-th Neumann eigenvalue of a convex domain $\Omega \subset \mathbb{R}^d$, we prove the following inequalities: for any $k\in \mathbb{N}$ there exists a…

Analysis of PDEs · Mathematics 2026-04-16 Dorin Bucur , Andrea Gentile , Antoine Henrot

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

A Laplacian eigenfunction on a two-dimensional manifold dictates some natural partitions of the manifold; the most apparent one being the well studied nodal domain partition. An alternative partition is revealed by considering a set of…

Spectral Theory · Mathematics 2015-09-10 Ram Band , David Fajman

In this paper, we investigate the eigenvalue problem for a non-local dispersal operator defined on a bounded spatial domain with Neumann-type boundary conditions. Unlike the classical Laplacian, the non-local operator lacks compactness,…

Spectral Theory · Mathematics 2026-05-26 Maciej Tadej