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1.
讨论线性过程Xk=∑∞i=-∞ai+kεi,其中{εi;-∞<i<∞}是均值为零,方差有限为σ2的双侧无穷独立同分布随机变量序列,{ai;-∞< i<∞}为绝对可和的实数序列.令Sn=∑nl=1Xk,n≥1,假设|ε1|3<∞,证明了对任意的δ>-1,lim ∈↘0∈2δ+2∑∞n=1(㏒ ㏒ n)δ/n3/2㏒ nE{|Sn|-∈τ√2n ㏒ ㏒ n}+=√2τ√/√π(δ+1)(2δ+3)Γ(δ+2),其中τ2=σ2(∑∞i=-∞ai)2以及Γ(·)为Gamma函数.  相似文献   

2.
讨论一类高阶亚纯系数非齐次线性微分方程解的零点问题,当方程的系数A0是亚纯函数且满足δ(∞,A0)=δ(0)和lim(r→∞)log T(r,Ao)/log r=∞时,如果f1和f2是方程f((k))+A(κ—1)f((k—1))+…+Aof=F的两个线性无关解,得到max{λ(f1),λ(f2)}=∞.还考虑了σ(F)=∞或Ad(1dκ—1)满足lim(r→∞)log m(r,Ad)/log r=∞的情况.  相似文献   

3.
陈才生  王如云 《数学学报》2001,44(6):1089-1098
文考虑双重退化抛物型方程ut=div(|u|r|u|m--2u)+A(u)带有零边界条件的初边值问题的整体解存在性,唯一性和解在t=0,∞处的L∞模估计.证明了当u0∈Lq(Ω)时,整体解u(t)满足估计‖u(t)‖∞≤C(1+t-λβ)(1+t)-β/M,‖(u(t)|r/(m-1)u(t))‖m≤C(1+t-μ)(1+t)-σ,t>0,这里λ,μ,σ,M,β为依赖于m,q,N和r的适当正常数.  相似文献   

4.
该文研究椭圆型方程{-Δpu+m|u|p-2u-Δqu+n|u|q-2u=g(x,u),x∈RN,u∈ W1,p(RN)∩W1,q(RN)弱解在全空间RN上的衰减性,其中m,n≥0,N≥3,1相似文献   

5.
在本文中,我们讨论了非线性常微分方程y"=a0|x|αy3 a1|x|βy2 α2|x|γy α3|x|δ振荡解的渐近表示.在这个方程中将α0,α,α1,β,α2,γ,α3,δ分别换成0,0,6,0,0,0,sgn(x),1就是著名的第一类Painleve方程,而将α0,α,α1,β,α2,γ,α3,δ分别换成2,0,0,0,sgn(x),1,α0,就是著名的第二类Painleve方程.当α0,α,α1,β,α2,γ,α3,δ分别换成-β/3γ,0,0,0,1/γ,1,α,0时,可用于组合KdV方程孤立子解的化简.  相似文献   

6.
关于一个平面二次系统极限环的唯一性   总被引:1,自引:0,他引:1  
陈兰荪 《数学学报》1977,20(1):11-13
<正> 我们这里研究平面二次系统容易知道方程(1)当δ=0时不存在闭轨与奇闭轨线,事实上只要引进变数变换d而且1+by=0是无切直线,因此当δ=0时(1)无闭轨与奇闭轨.因为(1)对于参数δ构成旋转向量场,因而我们知道(1)当δa(b+2l)≤0时在原点附近不存在极限环,而当δa(b+2l)>0且|δ|《1时在原点附近存在极限环,本文证明了(1)的极限环是唯一的.  相似文献   

7.
其中f,g为未知和已知的连续函数,而F=(f_1,f_2,…,f_m)~T和G=(g_1,g_2,…,g_m)~T为未知和已知的m元连续函数向量;A_i为m阶实常数矩阵,a_i,a_i为实常数,且|a_i|<1。鉴于(1.3)是方程(1.4)在m=1时的特款,将主要讨论函数矩阵方程(1.4)的数值解法。 在[2]中,我们曾给出了方程(1.4)的解存在唯一的两个充分条件,即 定理1 对函数矩阵方程(1.4),若存在实数μ≥0,使  相似文献   

8.
三维复Ginzburg-Landau方程的整体解的存在惟一性   总被引:2,自引:0,他引:2  
在三维空间中研究带2σ次非线性项的复值Ginzburg—Landau方程(CGL) ut=ρu (1 iγ)△u-(1 iμ)|u|^2σu,通过先验估计的方法,在适当的σ的假设下,获得该方程周期边值问题整体解的存在性和惟一性.  相似文献   

9.
本文研究退化椭圆型方程-Δxu-(α+1)2|x|~(2α)Δyu=|u|~(p-1)u,(x,y)∈Rm×Rk和方程-Δxu-(α+1)2|x|~(2α)Δyu=|u|~(p-1)u,(x,y)∈Π的Liouville型定理,其中-Δx-(α+1)2|x|~(2α)Δy是Grushin算子,Π={(x,y)∈Rm×Rk:x10}或{(x,y)∈Rm×Rk:y10}.本文将证明,当1p(Q+2)/(Q-2)时,上述方程Morse指数有限的有界解只有零解,其中Q=m+(α+1)k为齐次空间的维数,因此,本文将Laplace方程的结果推广到含Grushin算子的方程.  相似文献   

10.
主要证明了:设f(z)于开平面上超越亚纯,0δ1,且lim—r→∞(logT(r+1/r,f)/logT(r,f))+∞,则存在一列复数a_n(n=1,2,…),使集合{a:△_1)(a,f)δ}含于∩∞j=1∪∞n=j﹛a:|a-an|e-enσ﹜,其中σ=(log2/2-δ)/2([10/δ])0.即{a:△_(1))(a,f)δ为一有穷μ测度集.  相似文献   

11.
In this paper, using a new method (or framework), we establish the existence of global attractors for a class nonlinear evolution equation in , where the nonlinear term f satisfies a critical exponential growth condition.  相似文献   

12.
In this paper, we first provide some sufficient conditions for the existence of global compact random attractors for general random dynamical systems in weighted space (p?1) of infinite sequences. Then we consider the existence of global compact random attractors in weighted space for stochastic lattice dynamical systems with random coupled coefficients and multiplicative/additive white noises. Our results recover many existing ones on the existence of global random attractors for stochastic lattice dynamical systems with multiplicative/additive white noises in regular l2 space of infinite sequences.  相似文献   

13.
H.G. Rotstein et al. proposed a nonconserved phase-field system characterized by the presence of memory terms both in the heat conduction and in the order parameter dynamics. These hereditary effects are represented by time convolution integrals whose relaxation kernels k and h are nonnegative, smooth and decreasing. Rescaling k and h properly, we obtain a system of coupled partial integrodifferential equations depending on two relaxation times ɛ and σ. When ɛ and σ tend to 0, the formal limiting system is the well-known nonconserved phase-field model proposed by G. Caginalp. Assuming the exponential decay of the relaxation kernels, the rescaled system, endowed with homogeneous Neumann boundary conditions, generates a dissipative strongly continuous semigroup Sɛ, σ(t) on a suitable phase space, which accounts for the past histories of the temperature as well as of the order parameter. Our main result consists in proving the existence of a family of exponential attractors for Sɛ, σ(t), with ɛ, σ ∈ [0, 1], whose symmetric Hausdorff distance from tends to 0 in an explicitly controlled way.  相似文献   

14.
This paper is concerned with the global existence, exponentialstability of solutions and associated nonlinear C0-semigroupas well as the existence of maximal attractors in Hi (i = 1,2, 4) for a nonlinear one-dimensional thermoviscoelasticitydescribing a kind of solid-like material. Some new ideas andmore delicated estimates are employed to prove the global existenceand exponential stability of solutions. The important featurefor the existence of maximal attractors in Hi+ (i = 1, 2, 4)is that the metric spaces H1+, H2+ and H4+ we work with arethree incomplete metric spaces, as can be seen from the physicalconstraints, i.e. > 0 and u > 0, with and u being absolutetemperature and deformation gradient (strain). For any positiveparameters 1, 2, ..., 5 verifying some conditions, a sequenceof closed subspaces Hi Hi+ (i = 1, 2, 4) is found, and theexistence of maximal attractors in Hi (i = 1, 2, 4) is established.  相似文献   

15.
We consider the following doubly nonlinear parabolic equation in a bounded domain Ω??3: where the nonlinearity f is allowed to have a degeneracy with respect to ?tu of the form ?tu|?tu|p at some points x∈Ω. Under some natural assumptions on the nonlinearities f and g, we prove the existence and uniqueness of a solution of that problem and establish the finite‐dimensionality of global and exponential attractors of the semigroup associated with this equation in the appropriate phase space. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

16.
We study generalized viscous Cahn-Hilliard problems with nonlinearities satisfying critical growth conditions in , where Ω is a bounded smooth domain in Rn, n?3. In the critical growth case, we prove that the problems are locally well posed and obtain a bootstrapping procedure showing that the solutions are classical. For p=2 and almost critical dissipative nonlinearities we prove global well posedness, existence of global attractors in and, uniformly with respect to the viscosity parameter, L(Ω) bounds for the attractors. Finally, we obtain a result on continuity of regular attractors which shows that, if n=3,4, the attractor of the Cahn-Hilliard problem coincides (in a sense to be specified) with the attractor for the corresponding semilinear heat equation.  相似文献   

17.
First we establish some necessary and sufficient conditions for the existence of exponential attractors by using ωω-limit compactness and a measure of non-compactness. Then we provide a new method for proving the existence of exponential attractors. We prove the existence of exponential attractors for reaction–diffusion equations and 2D Navier–Stokes equations as simple applications.  相似文献   

18.
Let X1, X2, ..., Xn be independent and identically distributed random variables subject to a continuous distribution function F. Let X1∶n, X2∶n, ..., Xn∶n denote the corresponding order statistics. Write
((*))
where n, k are fixed integers. We apply a result of Marsaglia and Tubilla on the lack of memory of the exponential distribution finction assuming that certain distribution functions involving the above order statistics are equal in two incommensurable points τ1, τ2 > 0; this characterizes the exponential distribution. As a special case it turns out that the equality (*) assumed for s=1, 2 and x=τ1, τ2 implies that F is exponential. Proceedings of the XVII Seminar on Stability Problems for Stochastic Models, Kazan, Russian, 1995, Part II.  相似文献   

19.
Let (Ω,Σ,μ) a measure space such that 0<μ(A)<1<μ(B)<∞ for some A,BΣ. Under some natural conditions on the bijective functions φ,φ1,φ2,ψ,ψ1,ψ2:(0,∞)→(0,∞) we prove that if
  相似文献   

20.
First we establish some sufficient conditions for the existence of pullback exponential attractors by using $\omega-$limit compactness in the framework of process. Then we provide a new method to prove the existence of pullback exponential attractors. As a simple application, we prove the existence of pullback exponential attractors for nonautonomous reaction diffusion equations in $H_0^1$.  相似文献   

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