紧流形上的Schr?dinger算子的谱间隙估计

M是一个n维紧黎曼流形,具有严格凸边界,且Ricci曲率不小于(n-1)K(其中K≥0为某个常数).假定Schr?dinger算子的Dirichlet (或Robin)特征值问题的第一特征函数f₁在M上是对数凹的,该文得到了此类Schr?dinger算子的前两个Dirichlet(或Robin)特征值之差的下界估计,这推广了最近Andrews等人在Rⁿ中有界凸区域上关于Laplace算子的一个相应结果^[4].     

具有正Ricci曲率紧Riemann流形上的第一特征值估计

M为紧致n维Riemann流形，Ricci曲率具有正下界n-1，d是M的直径，本文证明了其Laplace算子的第一特征值λ1≥π^2/d^2 n-1/2。     

紧Riemann流形上的第一特征值估计

本文证明了[2]中提出的一个猜测设M是紧Riemann流形,其Ricci曲率具有负下界-K(K=const＞o),d是M的直径,则有λ1≥π2-d2-1/2K.为此,还给出了第一特征值下界的一个新估计     

紧Riemann流形上的第一特征值估计 *

设 M 是紧Riemann流形 ,其Ricci曲率具有负下界 -R(R >0 ) ,d是M的直径 ,证明了其Laplace算子的第一特征值λ1≥π²/d² - 0.52R ,且只要R≤ 5π² /3d² ,就有λ₁≥π²/d² - R/2 .     

小负曲率流形上Laplace算子第一特征值的下界估计

本文首先对流形的测地球上的Sobolev常数进行讨论,并利用它进行Moser迭代,最终得到具有小负曲率的闭的黎曼流形上Laplace算子特征值的一个下界估计.     

Ricci曲率具负下界的紧Riemann流形第一特征值估计

本文主要证明丘成桐教授的如下猜测:若M为紧致的m维Riemann流形,直径为d,Ricci曲率具负下界—R,R>0。设λ₁为M的第一特征值,则存在仅与m有关的常数C_m>0,使得λ₁≥π²/d² exp(-C_m(d²)^1/2)。在本文中,Cm=max((m-1)^1/2,2^1/2)。     

小负曲率流形上Laplace算子第一特征值的下界估计

本文首先对流形的测地球上的Sobolev常数进行讨论,并利用它进行Moser迭代,最终得到具有小负曲率的闭的黎曼流形上Laplace算子特征值的一个下界估计.     

紧Riemann流形的高阶特征值估计

对Ricci曲率具负下界的紧Riemann流形,本文获得了热方程正解优化的梯度估计及Harnack不等式,证明了高阶特征值下界定量估计的猜想．     

关于积流形的2形式上的 Laplace 算子的谱

本文主要讨论积流形上 Laplace 算子谱的唯一性,证明在一定条件下与CP~n×CP~n 的2形式上的 Laplace 算子谱相同的积流形必等度量同构于 CP~n×CP~n,且对 n=2时,在较弱的条件下证明了这个结果.     

紧致流形的第一特征值下界

对紧致Riemannian流形(无边或带有凸边界)的第一(Neumann)特征值,用流形的直径和Ricci曲率的下界,给出一些新的下界估计.     

Boundary Value Problems for the Stationary Schrodinger Equation on Riemannian Manifolds

We suggest a new approach to the statement of boundary value problems for elliptic partial differential equations on arbitrary Riemannian manifolds which is based on the consideration of equivalence classes of functions on a manifold. Using this approach, we establish some interrelation between the solvability of boundary value problems and solvability of exterior boundary problems for the stationary Schrodinger equation. Also we prove the comparison and uniqueness theorems for solutions to boundary value problems in this statement and obtain sufficient conditions for solvability of boundary value problems when the coefficient in the Schrodinger equation is changed.     

Infinity Behavior of Bounded Subharmonic Functions on Ricci Non-negative Manifolds

In this paper,we study the infinity behavior of the bounded subharmonic functions on a Ricci non-negative Riemannian manifold M.We first show that limr→∞r^2/V(r)∫B(r)△hdv=0if h is a bounded subharmonic function.If we further assume that the Laplacian decays pointwisely faster than quadratically we show that h approaches its supremun pointwisely at infinity,under certain auxiliary conditions on the volume growth of M.In particular,our result applies to the case when the Riemannian manifold has maximum volume growth.We also derive a representation formula in our paper,from which one can easily derive Yau‘s Liouville theorem on bounded harmonic functions.     

Functional Integrals for the Schrodinger Equation on Compact Riemannian Manifolds

In this paper, we represent the solution of the Cauchy problem for the Schrodinger equation on compact Riemannian manifolds in terms of functional integrals with respect to the Wiener measure corresponding to the Brownian motion in a manifold and with respect to the Smolyanov surface measures constructed from the Wiener measure on trajectories in the underlying space. The representation of the solution is obtained for the case of analytic (on some sets) potential and analytic initial condition under certain assumptions on the geometric characteristics of the manifold. In the proof, we use a method due to Doss and the representations via functional integrals of the solution to the Cauchy problem for the heat equation in a compact Riemannian manifold.     

基于谱隙的依全变差指数式收敛速度估计

利用与谱隙作比较的手法，本文研究可逆马氏过程依全变差的指数式收敛速度．我们证明在相当一般的情况下，只要对初分布略加限制，则此速度以谱隙为下界．进而，对于紧空间情形或生灭过程或半直线上的扩散，我们证得此速度等于谱隙．     

黎曼流形上混合边值问题的第一特征值估计

设M为一带边界M的紧致Riemann流形,本文考虑M上的下述混合边值条件的特征值问题 (△u+v_1u=0, u/n+αu|M=0,)其中n为M的外法向单位向量,α为一正常数。     

A Note on the First Eigenvalue of Hypersurfaces

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