具有非正系数的一阶中立型滞后微分方程的振动性和渐近性质

本文对较文[1,2]中更为广泛的具有非正系数的一类线性方程d/(dt)[x(t)+p(t)x(t-τ)]-Q(t)x(t-σ(t))=0,t≥t₀及非线性方程d/(dt)[x(t)+p(t)x(t-τ(t))]-Q(t)f(x(t-σ(t)))=0,t≥t₀进行了讨论,其中Q(t)∈C([t₀,+∞).R₊),得到了保证上述方程的所有有界解振动及非振动解当t→+∞时趋于零或±∞的一些充分性准则.     

二阶非线性中立型时滞微分方程的振动性

考虑二阶非线性中立型时滞分方程[a(t)|(z(t) p(t)x(t-τ))‘|^a-1(x(t) p(t)x(t-τ))‘]‘ q(t)|x(t-σ）|^a-1x(t-σ)=0(*)本文获得了方程（*)所有解振动的充分条件,推广并改进了[1]的结果。     

On the oscillation of the second order neutral delay differential equations

In this paper, we consider the oscillation of the second order neutral delay differential equations[x(t) cx(t-τ)]" p(t)x(t-σ)=0 (1)and obtain some sufficient conditions of the oscillation of (1) for the case c≥0, -1≤c<0 and c<-1.     

二阶拟线性中立型时滞微分方程的振动性

考虑二阶中立型时滞微分方程[a(t)|(x(t) p(t)x(t-τ)）′|^α-1(x(t) p(t)x(t-τ））′]′ f(t,x(t-σ））=0(E)其中α，τ，σ是非负常数，a(t),p(t)∈C([t0,∞），R），f(t,x)∈C(R,R)。建立了方程（E）的一些新的振动条件。     

具有变系数的二阶中立型差分方程

研究一类具有变系数的二阶中立型时滞差分方程 △τ^2[x（t）-c（t）x（t-τ）]=p（t）x（t-σ），t≥t0〉0 的解的振动性，给出了该类方程一切有界解振动的几个充分条件．     

中立型微分方程正解的存在性

考虑一阶具有正负系数中立型微分方程[x(t) -c(t)x(t -γ) ]+ p(t)x(t-τ) -Q(t)x(t-δ) =0 ,t≥t0 ,( )其中c,p ,Q ∈C( (t0 ,∞ ) ,R+) ,R+=( 0 ,∞ ) ,γ>0 ,t >δ≥ 0。我们获得了方程 ( )正解存在的充分条件。作为结果的推论 ,去掉了ZHANGBing_gen文 [4](《应用数学学报》1 996年第 2期 )中必需条件 ∫∞c0 p(t)dt=∞ ,其中 p(t) =p(t) -Q(t -τ+δ) ≥ 0 ,从而改进了文 [4]中相应结论。     

一类二阶微分方程的振动性

本文考虑二阶既具正系数又具负系数的时滞微分方程(x|¨)(t)+p(t)x(t-τ)-q(t)x(t-σ)=0 (*)(其中 p(t)、q(t)是[f_o,+∝)上的非负连续函数,τ、σ是正实数)的振动性。获得了方程(*)的所有有界解振动的充分性判据;以及在 p(t)、q(t)均为常数的情况下,获得了方程(1)的所有有界解振动的一些必要条件和充分必要条件。     

具有“积分小”系数的奇数阶中立型方程的振动性

考虑中立型微分方程dndtn[x( t) -P( t) x( t-τ) ]+Q( t) x( t-σ) =0 ,　 t≥ t0 ,( * )其中 n≥ 1 ,n为奇数 ,P( t) ,Q( t)∈ C( [t0 ,+∞ ) ,R+ ) τ>0 ,σ>0 .本文在不需要通常假设 ∫∞t0Q( s) ds=∞的条件下 ,获得了保证 ( * )的所有解振动的几个充分条件 ,并推广了文 [1 ]、[3]的相应结论 .     

某些一阶非齐次中立型微分差分方程的振动性

该文讨论了 d/dt[x(t) cx(t-τ)] P(t)x(t-σ) f(t)=0,t≥t_0一阶非齐次中立型微分差分方程的振动性.得到了一些方程振动的充分条件,推广了某些齐次方程的振动结果.     

一阶中立型时滞微分方程的振动性

通过构造适当的变换及有效函数,研究了一阶中立型时滞微分方程[x(t)-c(t)x(t-r)]′+p(t)f(x(t-τ))+∑ni=1qi(t)}f(x(t-σi))=0的振动性,获得了此方程所有解振动的n族充分条件.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

CONTENTS OF VOLUME 30

正~~     

Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].