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1.
In this paper, the following results have been proved: (i) If ( Xn,Fn ) is a uniformly integrable super(sub)-Mil, then (X.) lower (upper)-semiconverges (a. s. ) to an integrable random variable; (ii) If (Xn,Fn) is a uniformly integrable adapted sequence, then that (Xn) lower(upper)-semiconverges (a. s. ) is equivalent to that (Xn,Fn)is a super(sub)-Mil; and (iii) If (Xn,Fn) is a super(sub)-Mil of class (c-)((c+)), then (Xn) is lower(upper)-semiconvergent (a. s, ).  相似文献   

2.
邵振东  刘家壮 《应用数学》2004,17(4):596-602
图G的L( 2 ,1 )标号是一个从顶点集V(G)到非负整数集的函数f(x) .使得若d(x ,y) =1 .则|f(x) -f(y) |≥ 2 ;若d(x ,y) =2 ,则|f(x) -f(y)|≥ 1 .图G的L( 2 ,1 )标号数λ(G)是使得G有max{f(v) ∶v∈V(G) }=k的L( 2 ,1 )标号中的最小数k .本文将L( 2 ,1 ) 标号问题推广到更一般的情形即L( 3,2 ,1 ) 标号问题 .我们首先定义了图G的顶点 3 着色及图的 3 色数 χ3 (G)等有关概念 ,并推导出 3 色数 χ3 (G)的上界 ;然后根据 χ3 (G)与λ3 (G)的关系 ,得出了对一般图G ,有λ3 (G) ≤ 3maxH Gδ(H) (Δ2 -Δ 1 )这一一般关系式 ;最后证明了对一般平面图G ,有λ3 (G)≤ 1 5(Δ2 -Δ 1 ) ,并得出了其它几类平面图的λ3 (G)的上界 .  相似文献   

3.
主要研究了一种新型时滞积分不等式u(t)≤a(t)+∫0α(t)f(t,s)w(u(s))ds+∫0α(t)g(t,s∫)0sh(s,τ)φ(u(τ))dτds up(t)≤a(t)+p/p-q∫0α(t)(f(t,s)uq(s)w(u(s))+g(t,s)uq(s))dsup(t)≤a(t)+p/p-q∫0α(t)f(t,s)uq(s)w(u(s))ds+p/p-q∫0tg(t,s)uq(s)w(u(s))ds这里p>q≥0是常数且t∈[0,∞).并且用此结果研究了时滞微分积分方程解的全局存在性和有界性.  相似文献   

4.
Suppose {X(t); t≥ 0} is a single birth process with birth rate qii+l (i 〉 0) and death rate qij (i 〉 j ≥ 0). It is proved in this paper that (i) if there exists aconstant c≥ 0 such that b(i)-a(i)+ci is nondecreasing with respect to i and a(i) + u(i) - ci ≥ 0 (i≥ 0), then VarX(t)-EX(t)≥-X(0)e^-2ct,t≥0, or (ii) if there exists a constant u(i) - c≥ 0 such that b(i)-a(i)+ci is non-increasing with respect to i and a(i)+u(i)-ci≤0(i≥0),then VarX(t) - EX(t) ≤ -X(0)e^-2c,t ≥ 0 Hereb(i) = qii+1, a(0) = 0, a(i) = ∑j=^ijqii-j (i≥ 1), u(0) = u(1) =0 and u(i) = 1/2∑j=^ij(j - 1)qii-j (i ≥ 2) . This result covers the results for birth-death processes obtained in [7].  相似文献   

5.
一类奇异半线性热方程初值问题解 的唯一性结果   总被引:6,自引:0,他引:6  
蹇素雯  杨凤藻 《数学学报》2000,43(2):301-308
设u(t,x),u(t,x)为初值问题在带形域ST=(0,T)×Rn内的两个非负经曲解,f(x)连续有界非负的实函数,则有如下的结果:(1)若f(x)不恒为零,则在ST中u(t,x);(2)若γ>1,则在ST中u(t,x)u(t,x);(3)若0>γ>1,f(x)0,则问题(1.1),(1.2)的解不唯一且它的所有非平凡解的集合为u(t,s)=这里s≥0是参数,其中记号(γ)+=max{γ,0}.  相似文献   

6.
The main results of this paper are as follows;Let F be approximately continuous on[a,b]and g be of bounded variation on[a,b]. Then (APS)∫^ba Fexists if and only if (APS)∫^ba gdf existe. Furthermore,suppose (APS)∫^ba Fdy or (APS)∫^ba gdF exists, then we have (APS)∫^ba Fdg (APS)∫^bagdf=F(b)g(b)-F(a)g(a)  相似文献   

7.
Consider a nonlinear stochastic differential equations with respect to semimartingales (1) dY(t) = F{Y(t),t)dti(t) + G(t)dM(t)+f(Y(t),t)dti(t)+g(Y(t),t)dM(t), which might be regarded as a stochastic perturbed system of (2) dX(t) = F(X(t),t)dfi(t) + G(t)dM(t). Suppose Eq. (2) is exponentially stable almost surely. Under what conditions is Eq. (1) still exponentially stable almost surely? In this paper we will give some sufficient conditions. As an application we also discuss the almost sure exponential stability for semilinear stochastic systems and small stochastic perturbed systems  相似文献   

8.
设Y_(n×m)服从矩阵正态分布N(XΘ, σ^2Σ×V),X_(n×k)是一个列满秩的矩阵,n ≥k≥3,σ^2是未知的,σ^(-2)S_p服从自由度为p的χ^2分布。当f(t)是单调非降 可微的函数, 且0≤f(t)≤2(k-2)/m(p+2)时,其列向量为Δ_i(Y)=[I_k- f(V′_iY′(X′Σ^(-1)X)^(-2)YV_iS_p_(-1)S_p (X′Σ^(-1)X)^(-1)/V′_iY′(X′Σ^(-1)X)^(-2)YV_i](X′Σ^(-1)X)^(-1)X′Σ^(-1)Y_i的估计Δ(Y)在风险函数R_1或R_2下是能够改善Θ的极大似然估计(X′Σ^(-1)X)^(-1)X′Σ^(-1)Y.同时得到了Θ和CXΘ的线性可容许估计类.   相似文献   

9.
Let H and K be indefinite inner product spaces. This paper shows that a bijective map φ:B(H)→B(K) satisfies φ(AB B A) =φ(A)φ(5) φ(B) φ(A) for every pair A,B ∈B(H) if and only if either φ(A) = cU AU for all A or φ(A) = cUA U for all A; φsatisfies φ(AB A) = φ(A)φ(B) φ(A) for every pair A,B ∈B(H) if and only if either φ(A) = UAV for all A or φ(A) = UA V for all A, where A denotes the indefinite conjugate of A, U and V are bounded invertible linear or conjugate linear operators with U U = c-1I and V V = cI for some nonzero real number c.  相似文献   

10.
In this paper the new concept of B-posets is introduced. Some properties of B-posets and FS-posets are examined. Main results are: (1) Posets obtained from B-posets (FS-posets) by eliminating a proper upper subset, adding two or more finitely many incomparable maximal elements, taking vertical sums w.r.t. a maximal element are also B-posets (FS-posets); (2) A poset is a(n) B-domain (FS-domain) iff it is a Lawson compact B-poset (FS-poset); (3) The directed completions of B-posets (FS-posets) are B-domains (FS-domains); (4) The category B-POS (FS-POS) of B-posets (FS-posets) and Scott continuous maps is cartesian closed and has the category B-DOM (FS-DOM) of B-domains (FS-domains) and Scott continuous maps as a full reflective subcategory.  相似文献   

11.
主要研究了二阶微分系统具有奇异正定超线性周期边值问题多重正解的存在性问题,利用Leray-Schauder抉择定理和锥不动点定理给出了奇异正定超线性周期边值问题-(p(t)x′)′+q1(t)x=f1(t,x,y),t∈I=[0,1]-(p(t)y′)′+q2(t)y=f2(t,x,y)x(0)=x(1),x[1](0)=x[1](1)y(0)=y(1),y[1](0)=y[1](1)(1.1)的多重正解的存在性,其中非线性项fi(t,x,y)(i=1,2)在x=∞,y=∞点处超线性,在(x,y)=(0,0)处具有奇性.这里定义x[1](t)=p(t)x′(t),y[1](t)=p(t)y′(t)为准导数,其中系数p(t),qi(t)(i=1,2)是定义在[0,1]上的可测函数,且p(t)>0,qi(t)>0(i=1,2),a.e[0,1],fi(t,x,y)∈C(I×R×R,R+),R+=(0,+∞).  相似文献   

12.
测度链上非线性微分方程的三正解   总被引:1,自引:1,他引:0  
柏传志 《数学杂志》2004,24(4):361-364
运用文[1]中的Leggett—Williams不动点定理,我们给出了测度链上的非线性微分方程-x^△△(t)=f(t,x(σ(t))),t∈[a,b,]关于两点边值条件ax(a)-βx^△(a)=0,γx(σ(b)) δx^△(σ(b))=0三正解存在性准则。  相似文献   

13.
翟发辉 《数学学报》2001,44(2):307-310
本文证明了一类本质正规算子A'(Ω';1)(T∈A'(Ω';1),如果T满足(1)T,T|H(T)分别是本质正规算子;(2)σ(T)=Ω,ρF(T)∩σ(T)=Ω;(3)ind(T-λ)=-1,nul(T-λ)=0,λ∈Ω';(4)σ(T|H(T))是一完全集,这里Ω'是一连通的解析Cauchy域, Hl(T)= V{ker(T-λ)*:λ∈ρrs-F(T)}是模小紧相似的.  相似文献   

14.
本文定义了R^d中无界集合上的几种离散填充指标,并得到了若干性质,特别地,对任意给定的非空集合A属于R^d和任意正整数m,d^-imp^(m)(A)=dimp^(m)(A)=d^~imp^(m)(A^)=d^~imp^(m)(φ(A))=dimp^(m)(φ(A))=dimp^(2)(φ(A))。  相似文献   

15.
具有二次代数极限环线之方程■   总被引:3,自引:0,他引:3  
秦元勋 《数学学报》1958,8(1):23-35
<正> 可具有二次代数曲线为其极限环线,此事实并非显然.文献中至今未见至此种例子.本文对此类极限环线存在之充要条件,周期解之维一性,稳定性,结构之维一性,稳定性,具体算出之步骤等全部解决.  相似文献   

16.
陈建功 《数学学报》1960,10(1):33-40
<正> 1.設φ_o(x),φ_1(x),…是区間(a,b)上之一系列的就范直交函数,孟孝夫証明:当級数∑(a_n log log_n)~2收斂时,直交函数級数 a_oφ_o(x)+a_1φ_1(x)+…+a_nφ_n(x)+…(1)在{φ_o(x)}的直交区間中,几乎到处可用正阶蔡查罗(Cesaro)求和法——(C,a)求和法,a>0——求和.当a=1时,这个定理还有波尔根(Borgen)和卡契馬尔茲(Karczmarz)  相似文献   

17.
图G的一个k-正常边染色f被称为点可区别边染色是指任何两点的点及其关联边的色集合不同,所用最小的正整数k被称为G的点可区别边色数,记为X'_(vd)(G).用k_(2n)-E(C_m)表示2n阶完全图删去其中一条m阶路的边后得到的图,得到了K_(14)-E(C_4),K_(16)-E(C_4),K_(18)-E(C_5),K_(20)-E(C_5)的点可区别边色数分别为14,16,18,20.  相似文献   

18.
单位上三角矩阵群的注记   总被引:2,自引:2,他引:0  
记Tr_1(n,Z)是整数环Z上对角线元素全是1的全体上三角矩阵组成的群,k_(ij)(1≤i相似文献   

19.
姚云飞 《大学数学》2002,18(5):49-53
在赋范线性空间中考察下列几类泛函方程( ) f(x) g(y) =h(x+y) ,  ( ) f(x+y) =f(x) f(y) ,  ( ) f(x+y) =f(x) +f(y) +ag(x) g(y)的性质与解以及彼此之间的关系 .  相似文献   

20.
具p-Laplacian算子型奇异方程组边值问题正解的存在性   总被引:10,自引:0,他引:10  
刘斌 《数学学报》2005,48(1):35-50
本文讨论了一类具p-Laplacian算子型奇导方程组边值问题(φp(x'))'+α1(t),f(x(t),y(t))=0,(φp(y'))'+α2(t)g(x(t),y(t))=0,x(0)-β1x'(0)=0,x(1)+δ1x'(1)=0,y(0)-β2Y'(0)=0,y(1)+δ2y'(1)=0正解的存在性,其中φp(x)=|x|p-2x,p>1.通过使用不动点指数定理,在适当的条件下,建立了这类奇异方程组边值问题存在一个或者多个正解的充分条件.这些结果能用来研究椭圆型方程组边值问题径向对称解的存在性.  相似文献   

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