scholarly journals A Global Curvature Pinching Result of the First Eigenvalue of the Laplacian on Riemannian Manifolds

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Peihe Wang ◽  
Ying Li
Keyword(s):  
Lower Bound ◽  
Riemannian Manifolds ◽  
Negative Curvature ◽  
First Eigenvalue ◽  
Moser Iteration ◽  
The First Eigenvalue ◽  
Global Curvature ◽  
Sobolev Constant ◽  
Curvature Pinching

The paper starts with a discussion involving the Sobolev constant on geodesic balls and then follows with a derivation of a lower bound for the first eigenvalue of the Laplacian on manifolds with small negative curvature. The derivation involves Moser iteration.

scholarly journals Lichnerowicz-Obata Estimate, Almost Parallel p-form and Almost Product Manifolds

2021 ◽  
Author(s):  
Masayuki Aino
Keyword(s):  
Riemannian Manifolds ◽  
First Eigenvalue ◽  
Type Estimate ◽  
The First Eigenvalue ◽  
Hausdorff Approximation

AbstractWe show a Lichnerowicz-Obata type estimate for the first eigenvalue of the Laplacian of n-dimensional closed Riemannian manifolds with an almost parallel p-form ($$2\le p \le n/2$$ 2 ≤ p ≤ n / 2 ) in $$L^2$$ L 2 -sense, and give a Gromov-Hausdorff approximation to a product $$S^{n-p}\times X$$ S n - p × X under some pinching conditions when $$2\le p<n/2$$ 2 ≤ p < n / 2 .

scholarly journals A variation on the Donsker–Varadhan inequality for the principal eigenvalue

2017 ◽  
Vol 473 (2204) ◽  
pp. 20160877
Author(s):  
Jianfeng Lu ◽  
Stefan Steinerberger
Keyword(s):  
Lower Bound ◽  
Exit Time ◽  
Principal Eigenvalue ◽  
Short Paper ◽  
First Eigenvalue ◽  
Drift Diffusion ◽  
First Exit Time ◽  
The First Eigenvalue ◽  
Order Elliptic Operator ◽  
The Mean

The purpose of this short paper is to give a variation on the classical Donsker–Varadhan inequality, which bounds the first eigenvalue of a second-order elliptic operator on a bounded domain Ω by the largest mean first exit time of the associated drift–diffusion process via λ 1 ≥ 1 sup x ∈ Ω E x τ Ω c . Instead of looking at the mean of the first exit time, we study quantiles: let d p , ∂ Ω : Ω → R ≥ 0 be the smallest time t such that the likelihood of exiting within that time is p , then λ 1 ≥ log ( 1 / p ) sup x ∈ Ω d p , ∂ Ω ( x ) . Moreover, as p → 0 , this lower bound converges to λ 1 .

scholarly journals A survey on extensions of Riemannian manifolds and Bartnik mass estimates

2021 ◽  
pp. 1-30
Author(s):  
Armando Cabrera Pacheco ◽  
Carla Cederbaum
Keyword(s):  
General Relativity ◽  
Riemannian Manifolds ◽  
Gaussian Curvature ◽  
First Eigenvalue ◽  
Content Type ◽  
Asymptotically Flat ◽  
Adm Mass ◽  
Local Mass ◽  
Novel Technique ◽  
The First Eigenvalue

Mantoulidis and Schoen developed a novel technique to handcraft asymptotically flat extensions of Riemannian manifolds ( Σ ≅ S 2 , g ) (\Sigma \cong \mathbb {S}^2,g) , with g g satisfying λ 1 ≔ λ 1 ( − Δ g + K ( g ) ) > 0 \lambda _1 ≔\lambda _1(-\Delta _g + K(g))>0 , where λ 1 \lambda _1 is the first eigenvalue of the operator − Δ g + K ( g ) -\Delta _g+K(g) and K ( g ) K(g) is the Gaussian curvature of g g , with control on the ADM mass of the extension. Remarkably, this procedure allowed them to compute the Bartnik mass in this so-called minimal case; the Bartnik mass is a notion of quasi-local mass in General Relativity which is very challenging to compute. In this survey, we describe the Mantoulidis–Schoen construction, its impact and influence in subsequent research related to Bartnik mass estimates when the minimality assumption is dropped, and its adaptation to other settings of interest in General Relativity.

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