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In this paper, we consider the eigenvalue problem for Hodge-Laplacian on a Riemannian manifold $M$ isometrically immersed into another Riemannian manifold $\bar M$ for arbitrary codimension. We first assume the pull back Weitzenb\"{o}ck…

Differential Geometry · Mathematics 2017-12-18 Qing Cui , Linlin Sun

Lower bounds estimates are proved for the first eigenvalue for the Dirichlet Laplacian on arbitrary triangles using various symmetrization techniques. These results can viewed as a generalization of P\'olya's isoperimetric bounds. It is…

Spectral Theory · Mathematics 2008-07-17 Bartłomiej Siudeja

Motivated by relativistic materials, we develop a numerical scheme to support existing or state new conjectures in the spectral optimisation of eigenvalues of the Dirac operator, subject to infinite-mass boundary conditions. We study the…

Optimization and Control · Mathematics 2025-02-05 Pedro R. S. Antunes , Francisco Bento , David Krejcirik

We study the discretization of an elliptic partial differential equation, posed on a two- or three-dimensional domain with smooth boundary, endowed with a generalized Robin boundary condition which involves the Laplace-Beltrami operator on…

Numerical Analysis · Mathematics 2020-09-24 Dominik Edelmann

Eigenmaps are important in analysis, geometry, and machine learning, especially in nonlinear dimension reduction. Approximation of the eigenmaps of a Laplace operator depends crucially on the scaling parameter $\epsilon$. If $\epsilon$ is…

In this paper, we investigate a shape optimization problem for the second Robin eigenvalue of the weighted Laplacian on bounded Lipschitz domains symmetric about the origin. Our main theorem states that the ball centered at the origin…

Analysis of PDEs · Mathematics 2026-02-24 Yi Gao , Kui Wang , Anqiang Zhu

We consider the eigenvalue problem for the Laplace operator in a planar domain which can be decomposed into a bounded domain of arbitrary shape and elongated \branches" of variable cross-sectional profiles. When the eigenvalue is smaller…

Mathematical Physics · Physics 2016-10-05 Binh T. Nguyen , Andrey L. Delytsin , Denis S. Grebenkov

We introduce Robin boundary conditions for biharmonic operators, which are a model for elastically supported plates and are closely related to the study of spaces of traces of Sobolev functions. We study the dependence of the operator, its…

Analysis of PDEs · Mathematics 2021-05-25 Davide Buoso , James B. Kennedy

This paper is devoted to the asymptotic analysis of the eigenvalues of the Laplace operator with a strong magnetic field and Robin boundary condition on a smooth planar domain and with a negative boundary parameter. We study the singular…

Spectral Theory · Mathematics 2022-02-15 Rayan Fahs

We study the minimisation of the positive principal eigenvalue for an indefinite-weight problem under inhomogeneous Robin boundary conditions. The model is motivated by diffusive logistic equations in spatially heterogeneous environments,…

Spectral Theory · Mathematics 2026-04-01 Baruch Schneider , Diana Schneiderová , Yifan Zhang

The finite-rank Lieb-Thirring inequality provides an estimate on a Riesz sum of the $N$ lowest eigenvalues of a Schr\"odinger operator $-\Delta-V(x)$ in terms of an $L^p(\mathbb{R}^d)$ norm of the potential $V$. We prove here the existence…

Analysis of PDEs · Mathematics 2023-05-12 Rupert L. Frank , David Gontier , Mathieu Lewin

We prove that the first eigenvalue of the Dirichlet Laplacian for a triangle in the plane is bounded above by $\pi^2 L^2\over 9A^2$, where $L$ is the perimeter and $A$ is the area of this triangle. We show that the \mbox{constant 9} is…

Spectral Theory · Mathematics 2007-05-23 B. Siudeja

We get optimal lower bounds for the eigenvalues of the Dirac-Witten operator on locally reducible spacelike submanifold in terms of intrinsic and extrinsic expressions. The limiting-cases are also studied.

Differential Geometry · Mathematics 2023-07-12 Yongfa Chen

We consider the nonlinear eigenvalue problem, with Dirichlet boundary condition, for a class of very degenerate elliptic operators, with the aim to show that, at least for square type domains having fixed volume, the symmetry of the domain…

Analysis of PDEs · Mathematics 2018-03-21 Isabeau Birindelli , Giulio Galise , Hitoshi Ishii

We consider the magnetic Robin Laplacian with a negative boundary parameter. Among a certain class of domains, we prove that the disk maximizes the ground state energy under the fixed perimeter constraint provided that the magnetic field is…

Spectral Theory · Mathematics 2022-05-03 Ayman Kachmar , Vladimir Lotoreichik

We present some new bounds for the first Robin eigenvalue with a negative boundary parameter. These include the constant volume problem, where the bounds are based on the shrinking coordinate method, and a proof that in the fixed perimeter…

Spectral Theory · Mathematics 2018-11-26 Pedro R. S. Antunes , Pedro Freitas , David Krejcirik

The first nonzero eigenvalue of the Neumann Laplacian is shown to be minimal for the degenerate acute isosceles triangle, among all triangles of given diameter. Hence an optimal Poincar\'{e} inequality for triangles is derived. The proof…

Spectral Theory · Mathematics 2009-07-10 R. Laugesen , B. Siudeja

A computer-assisted proof is proposed for the Laplacian eigenvalue minimization problems over triangular domains under diameter constraints. The proof utilizes recently developed guaranteed computation methods for both eigenvalues and…

Numerical Analysis · Mathematics 2022-09-30 Ryoki Endo , Xuefeng Liu

We study the problem of minimizing the second Dirichlet eigenvalue for the Laplacian operator among sets of given perimeter. In two dimensions, we prove that the optimum exists, is convex, regular, and its boundary contains exactly two…

Analysis of PDEs · Mathematics 2010-11-29 Dorin Bucur , Giuseppe Buttazzo , Antoine Henrot

We consider elliptic operators with measurable coefficients and Robin boundary conditions on a bounded domain $\Omega \subset \mathbb{R}^d$ and show that the first eigenfunction $v$ satisfies $v(x) \ge \delta > 0$ for all $x \in…

Analysis of PDEs · Mathematics 2020-08-05 Wolfgang Arendt , A. F. M. ter Elst , Jochen Glück