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In K\"ahler-Einstein case of positive scalar curvature and even complex dimension, an improved lower bound for the first eigenvalue of the Dirac operator is given. It is shown by a general construction that there are manifolds for which…

Differential Geometry · Mathematics 2009-12-09 K. -D. Kirchberg

We prove the Fundamental Gap Conjecture, which states that the difference between the first two Dirichlet eigenvalues (the spectral gap) of a Schr\"odinger operator with convex potential and Dirichlet boundary data on a convex domain is…

Spectral Theory · Mathematics 2011-01-12 Ben Andrews , Julie Clutterbuck

In this paper, we give estimates for both upper and lower bounds of eigenvalues of a simple matrix. The estimates are shaper than the known results.

Numerical Analysis · Mathematics 2014-04-15 J. Chen

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

The fundamental gap is the difference between the first two Dirichlet eigenvalues of a Schr\"odinger operator (and the Laplacian, in particular). For horoconvex domains in hyperbolic space, Nguyen, Stancu and Wei conjectured that it is…

Differential Geometry · Mathematics 2024-04-25 Gabriel Khan , Malik Tuerkoen

We find lower and upper bounds for the first eigenvalue of a nonlocal diffusion operator of the form $ T(u) = - \int_{\rr^d} K(x,y) (u(y)-u(x)) \, dy$. Here we consider a kernel $K(x,y)=\psi (y-a(x))+\psi(x-a(y))$ where $\psi$ is a bounded,…

Analysis of PDEs · Mathematics 2011-11-18 L. I. Ignat , J. D. Rossi , A. San Antolin

We prove that for bounded and convex domains in arbitrary dimensions, the Maxwell constants are bounded from below and above by Friedrichs' and Poincare's constants, respectively. Especially, the second positive Maxwell eigenvalues in ND…

Analysis of PDEs · Mathematics 2018-11-07 Dirk Pauly

In the article we study the Neumann $(p,q)$-eigenvalue problems in bounded H\"older $\gamma$-singular domains $\Omega_{\gamma}\subset \mathbb{R}^n$. In the case $1<p<\infty$ and $1<q<p^{*}_{\gamma}$ we prove solvability of this eigenvalue…

Analysis of PDEs · Mathematics 2024-07-09 Prashanta Garain , Valerii Pchelintsev , Alexander Ukhlov

We give a new estimate on the lower bound for the first Dirichlet eigenvalue for a compact manifold with positive Ricci curvature in terms of the in-diameter and the lower bound of the Ricci curvature. The result improves the previous…

Differential Geometry · Mathematics 2007-05-23 Jun Ling

In [SWW], S. Seto, L. Wang and G. Wei proved that the gap between the first two Dirichlet eigenvalues of a convex domain in the unit sphere is at least as large as that for an associated operator on an interval with the same diameter,…

Differential Geometry · Mathematics 2017-06-01 Chenxu He , Guofang Wei

This paper gives a framework to produce the lower bound of eigenvalues defined in a Hilbert space by the eigenvalues defined in another Hilbert space. The method is based on using the max-min principle for the eigenvalue problems.

Numerical Analysis · Mathematics 2016-09-22 Hehu Xie , Chunguang You

We prove a lower bound on the first eigenvalue of the fractional Dirichlet-Laplacian of order $s$ on planar open sets, in terms of their inradius and topology. The result is optimal, in many respects. In particular, we recover a classical…

Analysis of PDEs · Mathematics 2024-02-21 Francesca Bianchi , Lorenzo Brasco

In this note we present upper bounds for the variational eigenvalues of the $p$-Laplacian on smooth domains of complete $n$-dimensional Riemannian manifolds and Neumann boundary conditions, and on compact (boundaryless) Riemannian…

Spectral Theory · Mathematics 2021-09-17 Bruno Colbois , Luigi Provenzano

We study Hadamard's variational formula for simple eigenvalues under dynamical and conformal deformations. Particularly, harmonic convexity of the first eigenvalue of the Laplacian under the mixed boundary condition is established for…

Analysis of PDEs · Mathematics 2024-09-09 Takashi Suzuki , Takuya Tsuchiya

In this article we study the first eigenvalues of closed Riemann surfaces for large genus. We show that for every closed Riemann surface $X_g$ of genus $g$ $(g\geq 2)$, the first eigenvalue of $X_g$ is greater than…

Differential Geometry · Mathematics 2022-11-02 Yunhui Wu , Yuhao Xue

We give lower and upper bounds for the first eigenvalue of geodesic balls in spherically symmetric manifolds. These lower and upper bounds are $C^{0}$-dependent on the metric coefficients. It gives better lower bounds for the first…

Differential Geometry · Mathematics 2011-02-19 Cleon S. Barroso , G. Pacelli Bessa

We study the boundary behaviour of a variant of the Fridman's invariant function (defined in terms of the Bergman metric) on Levi corank one domains, strongly pseudoconvex domains, smoothly bounded convex domains in $ \mathbb{C}^n $ and…

Complex Variables · Mathematics 2024-01-09 Rahul Kumar , Prachi Mahajan

Second order nonlinear eigenvalue problems are considered for which the spectrum is an interval. The boundary conditions are of Robin and Dirichlet type. The shape and the number of solutions are discussed by means of a phase plane…

Dynamical Systems · Mathematics 2025-04-11 Catherine Bandle , Simon Stingelin , Alfred Wagner

We compute the whole spectrum of the Dirichlet-to-Neumann operator acting on differential p-forms on the unit Euclidean ball. Then, we prove a new upper bound for its first eigenvalue on a domain $\Omega$ in Euclidean space in terms of the…

Differential Geometry · Mathematics 2012-02-17 Simon Raulot , Alessandro Savo

In this paper, we compute the second variation of the first Dirichlet eigenvalue on extremal domains in general Riemannian manifolds and establish a criterion for stability. We classify the stable extremal domains in the 2-sphere and…

Differential Geometry · Mathematics 2024-07-30 Marcos P. Cavalcante , Ivaldo Nunes