一类滞后量为[t]中立型泛函微分方程的渐进性和振动性

本讨论一类滞后量为[t]的中立型泛涵微分方程x′(t)-c(t)x′(t-[t] P(t)f(x(t-[t]))=0 t≥0的解的性质，得到所考虑的方程存在非振动解的充分条件和非零解的变化趋势。     

G型方程与GRONWALL型不等式

在本世纪初,T.H.Gronwall[1]建立了基本不等式如下:a(t),u(t)为[0,T]上非负连续函数,k 为非负常数,则由u(t)≤k+(?)a(s)u(s)ds,t∈[0,T]可以推出不等式u(t)≤kexp((?)a(s)ds),t∈[0,T].1956年,I.Bihari[2]得到推广的结果如下:     

一类滞后量为[t]的中立型泛函微分方程的渐进性和振动性

本文讨论一类滞后量为 [t]的中立型泛涵微分方程　　　　 x′(t) - c(t) x′(t- [t]+p(t) f(x(t- [t]) ) =0　 t≥ 0的解的性质 ,得到所考虑的方程存在非振动解的充分条件和非零解的变化趋势。     

星和轮的Mycielski图的[r,s,t]色数

给定非负整数r,s和t,若图G(V,E)有一个映射σ:V∪E→{0,1,…,k-1},k∈N,满足对V中相邻的点v_i,v_j有|σ(v_i)-σ(v_j)|≥r;对E中相邻的边e_i,e_j有|σ(e_i)-σ(e_j)|≥s;对V∪E中相关联的点v_i和边e_j有|σ(v_i)-σ(e_j)|≥t,则称σ为G的一个[r,s,t]-着色.使得图G存在使用了k种颜色的[r,s,t]-着色的最小整数k称为G的[r,s,t]-色数.研究星和轮的Mycielski图的[r,s,t]-着色,并给出其在一定条件下的[r,s,t]-色数.     

n维空间的Peano曲线

那汤松在文献[1]里,叙述了 Hilbert 关于平面上的 Peano 曲线的构造,并向读者提出了几个问题,其中第四个问题是:“构造三维空间的 Peano 曲线,即在给定的区间[0,1]上,构造这样的三个连续函数(?)(t)、(?)(t)、(?)(t),使所有的点((?)(t),(?)(t),(?)(t))的集合与立方体[0,1]×[0,1]×[0,1]重合”.本文将更一般地、解析地给出在 Jordan 意义下的 n 维欧氏空间的 Peano 曲线 (n≥2),即在区间 [0,1]上,给出 n 个连续函数x_1(t),x_2(t),…,x_n(t),使所有的点 (x_1(t),x_2(t),…,x_n(t))的集合与 n 维立方体[0,1]×[0,1]×…×[0,1] 重合.首先,在区间[0,2]上定义函数     

定积分換元法則的一点改进

通常所见Riemann积分换元公式的形式是:若φ(α)=a,φ(β)=b,则在适当条件下有 integral from a to b(f(x)dx)=integral from α to β(f[φ(t)]φ′(t)dt)。在常义R(Riemann)积分时须假定:f(x)在[a,b]上连续,φ(t),φ′(t)在[α,β]上连续。这时上述等式成立。或者假定:f(x)在[a,b]上R可积,φ(t),φ′(t)在[α,β]上连续,且φ′(t)≥0(或φ′(t)≤0,即φ(t)单调)。本文证明了:若f(x)在[a,b]上有界,φ(t)可表成R可积函数φ(t)的不定积分,则f(x)在[a,b]上R可积的充要条件为f[φ(t)]φ(t)在[α,β]上R可积,并且有上述等式成立(详见下文定理1)。     

循环矩阵环的局部化

本文的主要结果如下：(1)环R关于其乘法封闭子集S满足左Ore条件当且仅当R[σ1,σ2,…，σt]关于其相应乘法封闭子集S[σ1,σ2,…，σt]满足左Ore条件．(2)若R关于其乘法封闭子集S满足左Ore条件，S^-1 R是R关于S的左分式环，其自然同态为φ：R→S^-1R，则存在环同态φ：R[σ1,σ2,…,σt]→S[σ1,σ2,…,σt]^-1 R[σ1,σ2,…σt]使得(S-1R)[φ（σ1),φ-(σ2),…φ（σt)]≌S[σl，σ2，…，σt]^-1R[σ1,σ2,…σt]。     

不动点定理在奇摄动非线性初值问题的套层解中的应用

Singularperturbationofnonlinearboundaryvalueproblemswhichhavedoubleboundarylayerpropertieswerediscussedbysomeauthorsusingthemethodofdifferentialinequali ties[1 ] -[3 ] .Nonlinearboundaryvalueproblemswhichhavenotdoubleboundarylayerpropertieswerediscussedbysomeauthorsusingthemethodofthefixed_pointtheorem[4] -[6 ] .Inthispa perwewillusethefixed_pointtheoremtodiscussthethirdorderdifferentialequationswhichhavedoubleinitiallayer.Weconsiderthefollowingproblem .ε4y =h(t,y,εy′,ε2 y″,ε) ,t∈ [0 ,T…     

高维频谱有限函数的外推

在实轴 R~1上的限制.因此若已知 f(t)在 t∈[-T,T]上的值,则 f(t)在[-T,T]外的值就被唯一确定了.作为猜测,J.L.C.Sanz 和 T.S.Huang 于1983年提出了一种外推 f(t)在[-T,T]外的值的方法(见[1]).文献[2]和[3]从不同角度证实了这     

具有无限时滞的二阶微分方程解的存在性

§ 1.　IntroductionRecently ,thedifferentialequationswithdeviatingargumentswereusuallydiscussed(see[1 ],[4],[5 ]) .In [1 ],AGARWALRPandO’REGANDconsideredequationy″(t) =f(t,y(t) ,y(σ(t) ) ) ,　a.e .t∈ [0 ,1 ]y(t) =ψ(t) ,　　　　　　　　t∈ [-r ,0 ]y( 1 ) =a ,( )andtheydiscussedtheexistenceofatleastonesolutionforequation ( ) .Inthispaper ,weconsideramoregeneralequation-x″(t) =f(t ,xt) ,　t∈ [0 ,1 ]x(t) =ψ(t) ,　　　　t∈ ( -∞ ,0 ]x( 0 ) =x( 1 ) =0 ,( 1 .1 )andsomeexistencetheor…     

A time fractional functional differential equation driven by the fractional Brownian motion

Let $B^H$ be a fractional Brownian motion with Hurst index $H>\frac12$. In this paper, we prove the global existence and uniqueness of the equation $$ \begin{cases} ^CD_t^{\gamma}x(t)=f(x_t)+G(x_t)\frac{d}{dt}B^H(t),\ \ \ \ &t\in(0,T], \x(t)=\eta(t), \ \ \ \ \ &t\in[-r,0], \end{cases} $$ where $\max\{H,2-2H\}<\gamma<1$, $^CD_t^{\gamma}$ is the Caputo derivative, and $x_t\in \mathcal{C}_r=\mathcal{C}([-r,0],\mathbb{R})$ with $x_t(u)=x(t+u),u\in[-r,0]$. We also study the dependence of the solution on the initial condition.     

一类中立型高维周期微分系统的周期解

本文考虑中立型高维周期系统：其中（L,x）∈R×R~n,A（t,x）为连续函数矩阵,x_t∈C（[-γ,0],R~n）,x_t（θ）＝x（t十θ）,θ∈[-r,0],记C＝C（[-r,0］,R~n）,f：R×C→R~n连续,且A（t＋T,X）＝A（t,x）,T,r＞c∈R,本文用不动点方法研究此系统,得到了其周期解存在的充分性条件,所得结果推广、改进了文［1－3］中相应结论．     

Small idempotent clones I

G. Grätzer and A. Kisielewicz devoted one section of their survey paper concerning p _n-sequences and free spectra of algebras to the topic Small idempotent clones (see Section 6 of [18]). Many authors, e.g., [8], [14, 15], [22], [25] and [29, 30] were interested in p _n-sequences of idempotent algebras with small rates of growth. In this paper we continue this topic and characterize all idempotent groupoids (G, ·) with p ₂(G, ·) 2 (see Section 7). Such groupoids appear in many papers see, e.g. [1], [4], [21], [26, 27], [25], [28, 30, 31, 32] and [34].     

带非局部阻尼项的粘弹性方程解的衰减估计

In this paper,we consider the following viscoelastic equation u tt- △u +∫t 0 g(t-s)△u(s)ds + a(x)u t + u |u|r = 0 with initial condition and Dirichlet boundary condition.The decay property of the energy function closely depends on the properties of the relaxation function g(t) at infinity.In the previous works of [3,7,11],it was required that the relaxation function g(t) decay exponentially or polynomially as t → +∞.In the recent work of Messaoudi [12,13],it was shown that the energy decays at a similar rate of decay of the relaxation function,which is not necessarily dacaying in a polynomial or exponential fashion.Motivated by [12,13],under some assumptions on g(x),a(x) and r,and by introducing a new perturbed energy,we also prove the similar results for the above equation.     

半线性抛物方程在L2p空间中全局吸引子的存在性

本文研究了半线性抛物方程所生成的半群{S（t）}t≥0的吸引子的存在性.利用文献[1]中证明吸引子正则性的思想,分别得到半群{S（t）}t≥0在L^2p（Ω）空间中具有一个有界吸收集和一个全局吸引子.     

THE STRONG LAW OF LARGE NUMBER AND PARAMETER ESTIMATION OF ONE CLASS OF NON-NEGATIVE INTEGER-VALUED TIME SERIES

1.IntroductionLet{xt}beatimeseriesdefinedonprobabilityspace{fi,F,P),satisfyingwhere(1)p(t,s,j)isarandomfieldwithValueIor0,t,8EI={0,11,f2,'.},jEN={1,2,'.},andsatisfies(i)p{p(t,s,j)=0}=1whens>t;(1.2)(if)ac(tl,sl,jl)andp(tz,sa,j~)aremutuallyindependentwhenif/iZor81/s2;(ill)FOrfords,j,p(t,s,i)fort2sisanonhomogeneousMarkovChainwithtransitionprobabilityandinitialdistributiont=0T=0(2){Mt}isani.i.d.non-negativeinteger-valuedtimeseriesandindependentofn(t,sli).Inthefollowing,weassumeEMtz相似文献   

Best Partial Covering of a Convex Domain by Congruent Circles of a Given Total Area

Generalizing results of L. Fejes Toth [3], [5], we prove the following theorem. Let R be a convex domain of area |R| and let S be a finite family of at least two congruent circles of total area t. Then for the area |F| of the part of R covered by the circles of S, the inequality |F|< tf(|R|/t) holds, where f(x) is the area of the intersection of a circle of unit area and a regular hexagon of area x concentric with the circle.     

Darstellung skalarer und vektorwertiger Distributionen aus D′Lp durch Randwerte holomorpher Funktionen

In the present paper we show that every distribution T in D′_Lp (D′_Lp(E) in the vector-valued case) has a representation as boundary value of a holomorphic function T (with values in E). This problem was considered in [1], [5], [12]. The representing functions are characterized by growth conditions. It is shown that the conditions in [1] and [5] don't extend to the vector-valued case while the conditions in [12] do.     

三阶非线性系统的周期解

本文用作者在文[1]引进的S 稳定的概念,给出了下面三个三阶非线性系统x~■+ax″+bx′+integral(t,x)=0;x~■+ax″+integral(t,x′)+cx=0;x~■+integral(t,x″)+bx′+cx=0存在唯一稳定周期解的充分条件,推广和改进了文[2—3]的工作.