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1.
设H是一个可分的Hilbert空间,μ是H上的一个对称Gauss测度,λ1≥λ2≥…〉0是μ的共变算子的特征值,那么存在一个仅和t有关的正常数ct,使得对任意的r∈H μ{x∈H:‖x‖≤t}-μ{x∈H:‖x+r‖≤t}≤ct/(λ1λ2)^1/2‖r‖^2。  相似文献   

2.
关于山路定理的应用的一个注记   总被引:2,自引:0,他引:2  
研究了Dirichlet问题-Δu(x)=f(x,u),x∈Ω,u∈H10(Ω),其中Ω是RN(N≥1)中的有界光滑区域.在一定条件下,得到了下列结论:(i)当λ1<l<+∞且l≠λj,j≥2时,该问题存在正解;(i)当l=λj,j≥1,且limt→∞[f(x,t)t-2F(x,t)]=+∞时,存在非退化解;(ii)当l<λ1时,没有正解.  相似文献   

3.
衰减激励条件下确定性系统多新息辨识的收敛性分析   总被引:1,自引:0,他引:1  
在衰减激励条件下,分析了确定性系统多新息辨识算法的收敛性。得到了如下结果:1)当信息向量φ(t)有界时:(i)衰减指数ε>12时,估计误差θ(t)有界,即‖θ(t)‖=O(1)或‖θ(t)‖≤M<∞;(i)ε=12时,θ(t)以1tc(c>0)速度收敛于零,即‖θ(t)‖=O1tc;(ii)0<ε<12时,θ(t)以指数exp(-ct1-2ε)(c>0)速度收敛于零,即‖θ(t)‖=O(exp(-ct1-2ε))。2)当φ(t)以tμ速度增加(μ>0),即φ(t)=O(tμ)或‖φ(t)‖≤ctμ,c>0,(i)μ+ε>12时,θ(t)=O(1);(i)μ+ε=12时,θ(t)=O1tc,c>0;(ii)μ+ε<12时,θ(t)=O(exp(-ct1-2(μ+ε))),c>0。  相似文献   

4.
B值随机元阵列加权和的收敛性与大数定律   总被引:10,自引:0,他引:10  
令{Xni,1≤i≤kn↑∞,n≥1}为B值随机元阵列,{ani,1≤i≤kn,n≥1}为实数阵列。讨论加权和Sn=Σ↑kn↓i=1aniXni,n≥1的收敛性。在条件sup↓n,iP(‖Xni‖〉x)=0(x^-r)下给出了一些收敛性结果(1≤r〈p≤2),同时用这种收敛性刻划了Banach空间的p型性质。  相似文献   

5.
考虑下面高阶摄动方程解u(x,t)的LpLp′估计:tu+(-Δ)mu+V(x)u=0,u(x,0)=0,ut(x,0)=f(x),{x∈Rn,n>3m.假设势函数V(x)和初值f(x)具紧支集,V(x)是小势,则上面问题的解满足‖u(·,t)‖p′≤ct-d‖f‖p,t>0,这里m≥1,d=nm(1p-1p′)=1,1p+1p′=1,m2n≤1p-12<mn.  相似文献   

6.
讨论如下问题:δr/δt+λ1(r,s)δs/δt+λ2(r,s)δs/δx=0,[f(r,s)]x=x(t)=A(t),[r-ψ(s)]x=x(t)=0,其中λ1(r,s)与λ2(r,s)是已知函数,x=x(t)是非特征曲线,A(t)=dx/dt,f(r,s)及ψ(s)是已知的可微函数。求解区域是H=[(x,t)│(x〉x(t),A↓t}。在适当的假设下,文中采用速矢端变换,证明了上述问题的整体  相似文献   

7.
设X是Banach空间,X^*是其共轭空间,而(Ω,Σ,μ)是完备的有限测度空间。证明了:μ-可测的Dunford可积函数f:Ω→X是Pettis可积的,当且仅当标量值函数族{x^*f:‖x^*‖≤1}是一致可积的。  相似文献   

8.
本文讨论了初值问题{δu/δt-1/tΔu=u^r t〉ε0〉0 x≤R^n(0.1) u(ε0,x)=(x) x∈R^n(0.2)其中γ≥1,ψ(x)连续有界,且ψ(x)≥0但不恒为零。我们证明了当1/γ-1≥n/2时,初值问题(0.1)(0.2)的非负解必在有限时间blow-up。即问题(0.1)(0.2)在1/γ-1≥n/2时没有非负的整体解。  相似文献   

9.
本文在空间C(「ε0,T」,L^p)∩C^1(ε0,T「,L^内考虑边值问题 {δu/δt-1/t^αu=│u│^r-1u t〉ε0〉0 (1) limu t ↓ε0(t,x)=ψ(x) x∈R^n(2)其中γ〉1,p≥1,ε0是一个固定的正数。在L^p内ψ(x)≥0且不恒为零,α〉0,我们给出了问题(1)(2)有正解的一个必要条件,并研究了正解的不存在性。  相似文献   

10.
讨论下面方程的Cauchy问题:utt-Δu=|ut(x,t)|p,t≥0,x∈R3,u(x,0)=εf(x),ut(x,0)=εg(x),x∈R3,这里Δ=∑3i=12x2i,常数p>1,ε是正参数,H.Takamura(ComminPDE,1992,17(1&2):189)猜侧上面的Cauchy问题在p>2时是否对充分小的初值存在整体C2解.本文将在f(x),g(x)满足一定条件下在p>3时部分回答这个问题  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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