泛函不等式及其应用

本文介绍有关泛函不等式及谱理论与马氏过程研究的若干新进展，我们首先简要回顾了两个著名不等式，即Poincare不等式与对数不等式，然后分别使用泛函不等式研究本征谱、马氏半群的收敛速度和运费不等式．     

Functional Inequalities for the Decay of Sub-Markov Semigroups

A general functional inequality is introduced to describe various decays of semigroups. Our main result generalizes the classical one on the equivalence of the L ²-exponential decay of a sub-Markov semigroup and the Poincaré inequality for the associated Dirichlet form. Conditions for the general inequality to hold are presented. The corresponding isoperimetric inequality is studied in the context of diffusion and jump processes. In particular, Cheeger's inequality for the principal eigenvalue is generalized. Moreover, our results are illustrated by examples of diffusion and jump processes.     

Cauchy测度的两类加权泛函不等式

研究了一维Cauchy分布的加权Poincaré不等式和加权log-Sobolev不等式.我们给出并证明了所给权函数的最优性,同时对不等式中的常数进行了阶的估计.     

Rotenberg模型中迁移半群的本质谱

在Lp（1（≤）p＜＋∞）空间中,本文运用半群理论研究了Rotenberg模型中具光滑边界条件的迁移半群的本质谱.采用半群方法和比较算子等方法,证明了对任意的t＞0,s＞0,算子[UH（t）-U0（t）]U0（s）[UH（t）-U0（t）]在Lp（1＜p＜＋∞）在空间中紧和在L1空间弱紧,得到迁移半群VH（t）与V0（t）有相同的本质谱型.     

On Singular Functional Differential Inequalities

Classical theorems on differential inequalities [1, 2, 3] are generalized for initial value problems of the kind and where is a singular Volterra operator, is continuous and positive on ]a, b], is a norm in R ⁿ, and [u]₊ and [u]_– are respectively the positive and the negative part of the vector u R ⁿ.     

一类无穷维Hamilton算子的谱

研究了一类无穷维Hamilton算子的近似点谱及本质谱.进而通过无穷维Hamilton算子内部元素的乘积的谱对整体谱进行了刻画,最后证明了结论的正确性.     

Controlling Inflation: The Infinite Horizon Case

This paper studies the two-dimensional singular stochastic control problem over an infinite time-interval arising when the Central Bank tries to contain the inflation by acting on the nominal interest rate. It is shown that this problem admits a variational formulation which can be differentiated (in some sense) to lead to a stochastic differential game with stopping times between the conservative and the expansionist tendencies of the Bank. Substantial regularity of the free boundary associated to the differential game is obtained. Existence of an optimal policy is established when the regularity of the free boundary is strengthened slightly, and it is shown that the optimal process is a diffusion reflected at the boundary. Accepted 22 May 1998     

具无限时滞的中立型随机泛函微分方程解的存在唯一性

The main aim of this paper is to establish the existence-and-uniqueness theorem for neutral stochastic functional differential equations with infinite delay at phase space BC（（-∞, 0]; R^n） An example is given for illustration.     

算子的Kato本质谱与Browder本质谱的连通分支

利用算子谱的精密结构的分析方法,给出算子S和T拟相似时Kato本质谱σK(S)的一个连通分支与σK(T)相交的充分条件和充要条件,同时证明了Browder本质谱σB(S)的每一个连通分支与Kato本质谱σK(T)的某些子集的交集是非空的.     

算子的左本质谱与Browder本质谱

设算子S和T拟相似,应用算子谱的精密结构的分析,证明了Browder本质谱σB(S)的连通分支与σB(T)的某些子集的相交关系以及左本质谱σle(S)的连通分支与本质谱σe(T)的某些子集的相交关系,给出左本质谱σle(S)的连通分支与σle(T)相交的充分条件和充要条件.     

球面上的次临界最佳Sobolev不等式

本文在球面SN上建立了一类最佳Sobolev不等式:‖f‖2Lq(SN)≤(q-2)Γ(N-d)2+1/dΓ(N+d/2))(∫SNf(ξ)Adf(ξ)dξ-Γ(N+d/2)Γ/(N-d/2)∫SN |f丨2dξ)+∫SN丨f丨2dξ,其中Ad(0＜d＜N)是SN上的高阶保形算子,dξ是SN的归一化曲面测度,2≤q＜2...     

Functional Inequalities for Particle Systems on Polish Spaces

Various Poincaré–Sobolev type inequalities are studied for a reaction–diffusion model of particle systems on Polish spaces. The systems we consider consist of finite particles which are killed or produced at certain rates, while particles in the system move on the Polish space interacting with one another (i.e. diffusion). Thus, the corresponding Dirichlet form, which we call reaction–diffusion Dirichlet form, consists of two parts: the diffusion part induced by certain Markov processes on the product spaces Eⁿ (n≥1) which determine the motion of particles, and the reaction part induced by a Q-process on ℤ₊ and a sequence of reference probability measures, where the Q-process determines the variation of the number of particles and the reference measures describe the locations of newly produced particles. We prove that the validity of Poincaré and weak Poincaré inequalities are essentially due to the pure reaction part, i.e. either of these inequalities holds if and only if it holds for the pure reaction Dirichlet form, or equivalently, for the corresponding Q-process. But under a mild condition, stronger inequalities rely on both parts: the reaction–diffusion Dirichlet form satisfies a super Poincaré inequality (e.g., the log-Sobolev inequality) if and only if so do both the corresponding Q-process and the diffusion part. Explicit estimates of constants in the inequalities are derived. Finally, some specific examples are presented to illustrate the main results. Mathematics Subject Classifications (2000) 4FD0F, 60H10. Feng-Yu Wang: Supported in part by the DFG through the Forschergruppe “Spectral Analysis, Asymptotic Distributions and Stochastic Dynamics”, the BiBoS Research Centre, NNSFC(10121101), and RFDP(20040027009).     

Approximate Controllability of Neutral Stochastic Functional Differential Systems with Infinite Delay

In this article, we consider a class of control systems governed by the neutral stochastic functional differential equations with unbounded delay and study the approximate controllability of the system. An example is given to illustrate the result.     

L2×L2中的一类无穷维Hamilton算子的剩余谱

该文得到了一类无穷维Hamilton算子的剩余谱和点谱存在的几个判别准则,从而给出 了求其剩余谱和点谱的方法．在此基础上构造了L2×L2中无穷维Hamilton算子的剩余谱 非空的具体例子,从而进一步验证了判别准则的有效性．     

上三角无穷维Hamilton算子的剩余谱

将点谱划分为四个部分,得到上三角无穷维Hamilton算子的点谱σ_p(H)关于虚轴对称的充要条件.在此基础上,结合无穷维Hamilton算子的谱结构,得到无穷维Hamilton算子剩余谱的完全描述,从而实现了利用其内部算子刻画剩余谱.     

一些Pachpatte不等式的加强与反向形式

本文建立了一些新的加强和反向Pachpatte不等式.作为应用,推广和加强了一些新型Hilbert不等式.     

Hysteresis and Hemivariational Inequalities: Semilinear Case

In this paper we consider semilinear parabolic boundary value problems having nonsmooth and nonmonotone behaviour and memory effects. The mathematical problem can be formulated and studied by using the notions of hemivariational inequality (based on the generalized gradient in the sense of F.H. Clarke) and the hysteresis operator. We establish two general existence results for such problems. Applications from mechanics illustrate the theory.     

四元数矩阵积的特征值与奇异值的不等式

运用优化不等式理论和四元数体上的几何理论 ,得到了四元数矩阵积的特征值与奇异值的几个不等式 .     

板几何中具反射边界条件的迁移算子的谱

在LP(1p<∞)空间研究了板几何中一类带反射边界条件具各向异性、连续能量、均匀介质迁移算子的谱,证明了该迁移算子生成C0半群的Dyson-Phillips展开式的二阶余项在LP(1相似文献   

一类Schrdinger算子的连续谱测度(英文)

考虑ｌ２（Ｚ）上的离散Ｓｃｈｒｏｄｉｎｇｅｒ算子，其势Ｖｎ是一个由ｋ＋１个符号｛０，１，２，…，ｋ｝构成的序列．证明了它具有纯连续谱．