首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 67 毫秒
1.
Consider a backward heat equation in a bounded domain Ω (?) R2 with the noisy data in the initial time geometry. The aim is to find the temperature for 0 < ε < t < T. For this ill-posed problem, the authors give a continuous dependence estimate of the solution. Moreover, the convergence rate of the approximate solution is also given.  相似文献   

2.
An SIS epidemic model with a simple vaccination is investigated in this article. The efficiency of vaccine, the disease-related death rate and population dynamics are also considered in this model. The authors find two threshold R0 and Rc (Rc may not exist). There is a unique endemic equilibrium for R0 > 1 or Rc = R0; there are two endemic equilibria for Rc < R0 < 1; and there is no endemic equilibrium for R0 < Rc < 1. When Rc exists, there is a backward bifurcation from the disease-free equilibrium for R0 = 1. They analyze the stability of equilibria and obtain the globally dynamic behaviors of the model. The results acquired in this article show that an accurate estimation of the efficiency of vaccine is necessary to prevent and controll the spread of disease.  相似文献   

3.
Suppose X is a super-α-stable process in Rd, (0<α<2), whose branching rate function is dt, and branching mechanism is of the form ■(z) = z1 β(0 <β≤1). Let Xr and Yr denote the exit measure and the total weighted occupation time measure of X in a bounded smooth domain D, respectively. The absolute continuities of Xτ and Yτ are discussed.  相似文献   

4.
A matching is extendable in a graph G if G has a perfect matching containing it. A distance q matching is a matching such that the distance between any two distinct matching edges is at least q. In this paper, we prove that any distance 2k-3 matching is extendable in a connected and locally(k-1)-connected K1,k-free graph of even order. Furthermore, we also prove that any distance q matching M in an r-connected and locally(k-1)-connected K1,k-free graph of even or...  相似文献   

5.
The purpose of this paper is to discuss representations of high order C0finite element spaces on simplicial meshes in any dimension.When computing with high order piecewise polynomials the conditioning of the basis is likely to be important.The main result of this paper is a construction of representations by frames such that the associated L2condition number is bounded independently of the polynomial degree.To our knowledge,such a representation has not been presented earlier.The main tools we will use for the construction is the bubble transform,introduced previously in[1],and properties of Jacobi polynomials on simplexes in higher dimensions.We also include a brief discussion of preconditioned iterative methods for the finite element systems in the setting of representations by frames.  相似文献   

6.
Foot-and-mouth disease is one of the major contagious zoonotic diseases in the world.It is caused by various species of the genus Aphthovirus of the family Picornavirus,and it always brings a large number of infections and heavy financial losses.The disease has become a major public health concern.In this paper,we propose a nonlocal foot-and-mouth disease model in a spatially heterogeneous environment,which couples virus-to-animals and animals-to-animals transmission pathways,and investigate the dynamics of the disperal.The basic reproduction number R0is defined as the spectral radius of the next generation operator R(x)by a renewal equation.The relationship between R0and a principal eigenvalue of an operator L0is built.Moreover,the proposed system exhibits threshold dynamics in terms of R0,in the sense that R0determines whether or not foot-and-mouth disease invades the hosts.Through numerical simulations,we have found that increasing animals'movements is an effective control measure for preventing prevalence of the disease.  相似文献   

7.
Consider the system of integral equations with weighted functions in Rn,{u(x) =∫Rn|x-y|α-nQ(y)v(y)qdy1,v(x)=∫Rn|x-y|α-nK(y)u(y)pdy,where 0 < α < n,1/(p+1) + 1/(q+1)≥(n-α)/n1,α/(n-α) < p1q < ∞1,Q(x) and K(x) satisfy some suitable conditions.It is shown that every positive regular solution(u(x)1,v(x)) is symmetric about some plane by developing the moving plane method in an integral form.Moreover,regularity of the solution is studied.Finally,the nonexistence of positive solutions to the system in the case 0 <...  相似文献   

8.
This paper is concerned with the parabolic-parabolic-elliptic system ■in a bounded domain Ω?Rn with a smooth boundary,where the parameters χ,ζ12 are positive constants and m≥1.Based on the coupled energy estimates,the boundedness of the global classical solution is established in any dimensions(n≥1) provided that m>1.  相似文献   

9.
Saturating contact rate of individual contacts is crucial in an epidemiology model.A mathematical SIR model with saturation incidence and age of infec- tion is formulated in this paper.In addition,we study the dynamical behavior of this model and define the basic reproductive number R_0.The authors also prove that the diseased-free equilibrium is globally asymptotically stable if R_0<1. The endemic equilibrium is locally asymptotically stable if K_1>αand R_0>1.  相似文献   

10.
The generalized conjugate phase retrieval problem aims to reconstruct a complex signal x ∈ Cn from quadratic measurements x*A1x,...,x*Amx,where A1,...,Am∈Rn×n are real symmetric matrices.The equivalent formulation for generalized conjugate phase retrieval along with the minimal measurement number required for accurate retrieval(up to a global phase factor as well as conjugacy) is derived in this paper.We present a set of nine vectors in R4 and prove that it is conjugate phase retrievable on C4.This result implies the measurement number bound 4n-6 is not optimal for some n,which confirms a conjecture in the article by Evans and Lai(2019).  相似文献   

11.
两类正规化双全纯映照子族齐次展开式的精细估计   总被引:2,自引:0,他引:2  
刘小松  刘太顺 《数学学报》2007,50(2):393-400
本文考虑C~n中单位多圆柱上和一般复Banach空间中单位球上的正规化双全纯α(0■α<1)次的殆β(-π/2<β<π/2)型螺形映照以及α(0<α<1)次的β(-π/2<β<π/2)型螺形映照f(其中x=0是f(x)-x的k+1阶零点),研究了它们的构造,并得到其齐次展开式的精细估计.所得的结果推广了以前相应的结论.  相似文献   

12.
翟文广  曹晓东 《数学进展》2003,32(6):706-721
本文证明了如果1相似文献   

13.
研究具有N策略和负顾客的反馈抢占型M/G/1重试可修排队模型的时间依赖解的渐近行为.当初步服务的失效率函数η(x),主要服务的失效率函数μ(x)和修理时间的失效率函数ψ(x)满足0η≤η(x)≤η∞,0μ≤μ(x)≤μ∞,0ψ≤ψ(x)≤ψ∞并且η(x)是Lipschitz连续函数时,证明模型的时间依赖解指数稳定.  相似文献   

14.
杨继明 《数学学报》2007,50(3):653-660
本文给出有限域F=F_q(q=p~f,f≥1,p是一个奇素数)上一类方程组∑_(i=s_(r-1)+1~(s_r)∑_(j=1)~(m_i-m_(i-1))a_(m_(i-1)+j)x_1~(d_m(i-1)+j,1)…x_(n_i)~d_(m_(i-1)+j,n_i)=b_r,r=1,…,k当指数满足一定条件时,在F~(n_s_k)上解数的一个直接公式,这里d_(ij)>0,a_i∈F~*,b_i∈F,0= s_0<s_1<…<s_k,0=m_0<m_1<…<m_(s_k),0=n_0<n_1<…<n_(s_k), m_1≤n_1,…,m_(s_k)≤n_(s_k).  相似文献   

15.
二阶三点半正边值问题正解的存在性   总被引:1,自引:0,他引:1  
利用锥的Krasnosel'skill不动点定理建立了二阶三点半正边值问题u″+λf(t,u)+δg(t,u)=0, t∈(0,1),u(0)=0, αu(η)=u(1).其中,λ,δ>0, 0<η<1, 0<αη<1正解的存在性,这里,非线性项不需要是非负的.  相似文献   

16.
This paper is devoted to study the classification of self-similar solutions to the m ≥ 1,p,q > 0 and p + q > m. For m = 1, it is shown that the very singular self-similar solution exists if and only if nq + (n + 1)p < n + 2, and in case of existence, such solution is unique. For m > 1, it is shown that very singular self-similar solutions exist if and only if 1 < m < 2 and nq + (n + 1)p < 2 + mn, and such solutions have compact support if they exist. Moreover, the interface relation is obtained.  相似文献   

17.
The existence, uniqueness, multiplicity and asymptotic behavior of the solutions to the equation are studied by means of variational and sub-sup-solution methods, where 0 < q < p <1, Ω RN with N > 3 is a smooth bounded domain, a, b ∈ L∞(Ω) and λ ∈ R1 is aparameter.  相似文献   

18.
设{W(t),t≥0}是一标准Wiener过程,记S是Strassen重对数律的紧集类·本文中我们讨论了两个变量sup0≤t≤1-h inff∈S sup0≤x≤1 |(W(t+hx)-W(t))(2h log h-1)-1/2 - f(x)|及inf0≤t≤1-h sup0≤x≤1 |(W(t + hx) - W(t))(2hlogh-1)-1/2- f(x)|(对任何f∈S)趋于零的精确的收敛速度.作为一个推广,我们建立了Wiener过程的不可微模与泛函的连续模之间的一种关系.  相似文献   

19.
蔡光辉 《应用数学》2003,16(3):8-12
设{Y,Yi,-∞<i<∞}为一负相伴同分布随机变量序列,{ai,-∞<i<∞}绝对可和的实数序列,本文在适当的条件下,证明了平滑移动过程{∑k=1^n∑i=-∞^∞ai k Yi/n^1/t,n≥1}的完全收敛性.所得的结果改进了[1]中的定理1.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号