宏观经济均衡发展的数学理论(Ⅲ)

研究了前向延迟型动态投入产出模型X(t)=AX(t 1) B[X(t 1)-x(t)]和X(t)=AX(t 1) B[X(t 1)-X(t)] S(t)的解向量和A B的系数对经济发展的影响，证明了使经济崩溃的向量集合的存在性．对X(t)=AX(t 1) B[X(t 1)-X(t)]前向延迟型动态投入产出模型，给出了经济发展的最快速度；证明了降低消耗系数和投资系数将提高经济效率和经济发展速度．     

Clifforrd分析中广义双正则函数的(线性)非线性边值问题

本文研究Ｃｌｉｆｏｒｄ分析中广义双正则函数的一个非线性边值问题：Ａ（ｔ１，ｔ２）Ｗ＋＋（ｔ１，ｔ２）＋Ｂ（ｔ１，ｔ２）Ｗ＋－（ｔ１，ｔ２）＋Ｃ（ｔ１，ｔ２）Ｗ－＋（ｔ１，ｔ２）＋Ｄ（ｔ１，ｔ２）Ｗ－－（ｔ１，ｔ２）＝ｇ（ｔ１，ｔ２）ｆｔ１，ｔ２，Ｗ＋＋（ｔ１，ｔ２），Ｗ＋－（ｔ１，ｔ２），Ｗ－＋（ｔ１，ｔ２），Ｗ－－（ｔ１，ｔ２）［］．先讨论解的积分表示式，再研究几个奇异算子，最后用Ｓｃｈａｕｄｅｒ不动点原理（压缩映射定理）证明了解的存在性（唯一性）．目前还没有见到其它国内外学者研究广义双正则函数的非线性边值问题．本文推广了Ｆ．Ｂｒａｃｋｓ，Ｗ．Ｐｉｎｃｋｅｔ［１０］，ＬｅＨｕａｎｇ Ｓｏｎ［１１］，Ｒ．Ｐ．ＧｉｌｂｅｒｔａｎｄＪ．Ｌ．Ｂｕｃｈｎａｎ［１５］和黄沙［１３］的工作     

The Solvability of the Boundary Value Problem of the Four Elements with the Carleman Shift and Complex-conjugate Values

To following boundary value problem a(t)\overline{Φ^+(t)} + b(t)Φ^+[α(t)] + c(t)\overline{Φ^-(t)} + d(t)Φ^-[a(t)] = f(t) this paper has given out the number of linearly independent solutions and the conditions of solvability, so as to deepen the study of the problem to the same level as that of following problem a(t)\overline{Φ^+(t)} + b(t)Φ^+(t) + c(t)\overline{Φ^-(t)} + d(t)Φ^-(t) = f(t)     

变更图的直径

对于给定的正整数t和d(≥2),用F(t,d)和P(t,d)分别表示在所有直径为d的图和路中添加t条边后得到的图的最小直径,用f(t, d)表示从所有直径为d的图中删去t条边后得到的图的最大直径. 已经证明P(1, d)=(d)/(2), P(2,d)=(d 1)/(3)和P(3, d)=(d 2)/(4). 一般地,当t和d≥4时有(d 1)/(t 1)-1≤P(t, d)≤(d 1)/(t 1) 3. 在这篇文章中,我们得到F(t, f(t, d))≤d≤f(t, F(t, d))和(d)/(t 1)≤F(t, d)=P(t, d)≤(d-2)/(t 1) 3,而且当d充分大时,F(t, d)≤(d)/(t) 1. 特别地,对任意正整数k有P(t, (2k-1)(t 1) 1)=2k,当t=4或5,且d≥4时有(d)/(t 1)≤P(t, d)≤(d)/(t 1) 1.     

An inequality for steiner systems II

It is proved that if a Steiner systemS(t, k, v), witht < k < v, hast odd andv > (t + 1)(k – t + 1), thenv (t + 2)(k – t + 1) (Theorem 1). The caset is even is also considered and a characterization ofS(t, t + 1, 2t + 3), S(t, t + 1, 2t + 5), S(t, t + 2, 3t + 6) andS(t, t + 2, 3t + 7) is given (Theorem 2).     

PERIODIC SOLUTIONS OF SCALAR NEUTRAL VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS WITH INFINITE DELAY

This paper deals with the existence and uniqueness of periodic solutions of the following scalar neutral Volterra integro-differential equation with infinite delaywhere a, C, D, f are continuous functions, also a(t + T) = a(t), C(t + T,s + T) = C(t, s), D(t + T,s + T) = D(t, s), f(t + T) = f(t). Sufficient conditions on the existence and uniqueness of periodic solution to this equation are obtained by the contraction mapping theorem.     

周期系数的平面Hamilton系统的平衡解的稳定性

本文考虑周期系数的平面Hamilton系统H(x,y,t)=H2(x,y,t)+H4(x,y,t)+d(x,y,t)的平衡解的稳定性。其中H2(x,y,t)=1/2[a(t)x2+y2],H4(x,y,t)=b4(t)x4+b2(t)(xy)2+b0(t)y4以及a(t),b0(t),b2(t),b4(t)是连续的T-周期函数,d(x,y,t)关于时间也是T-周期,在原点附近其阶为(x2+y2)3.     

圈的多重联图的邻点可区别E-全染色的一些结果

记χ_(at)~e(C_n_i)为n_i阶的圈C_n_i的邻点可区别E-全色数.若n_i≡0(mod 2)(i=1,2,3…,t),则χ_(at)~e(C_n_1+C_n_2+…+C_n_t)=2t;若n_i≡0(mod 2)(i=1,2,3…,r,l相似文献   

中立型标量积分微分方程的周期解

本文考虑中立型标量方程x′(t)=a(t)x(t)+∫     

A problem of adaptive control with standard model

We consider the problem of adaptive control by a linear stochastic system with lag

The stability of RDDE\ddot x(t) + p_1 (t)\dot x(t) + q_1 (t)x(t) + p_2 (t)\dot x(t - r(t)) + q_2 (t)x(t - r(t)) = O

In this paper, the author considered the stability of zero solution of linear RDDE $$\begin{gathered} \ddot x(t) + p_1 (t)\dot x(t) + q_1 (t)x(t) + p_2 (t)\dot x(t - r(t)) + q_2 (t)x(t - r(t)) = O, \hfill \\ \ddot x(t) + p_1 (t)\dot x(t) + q_1 (t)x(t) + p_2 (t)\dot x(t - r(t)) = O \hfill \\ \end{gathered} $$ using Liapunov-Razumikhin functional and transformations and obtained some sufficient conditions for the stability of Eqs.(1) and (2). These results are suitable both for boundedp _i (t),q _i (t) andr(t).i=1,2.     

奇异伪辛群的Carter子群

设 Fq是特征为 2的有限域 ,本文研究了 Fq上 2 ν+δ+t级奇异伪辛群 Ps2ν+δ+ t(Fq) (δ=1或 2 )的 Carter子群的存在性及结构 .得到的结果为 :若 q>2 ,Ps2ν+δ+ t(Fq)中不含 Carter子群 ,若 q=2 ,Ps2ν+δ+ t(Fq)的 Carter子群为它的 Sylow2 -子群的正规化子 .     

Approximate Controllability for Semilinear Systems

The relations between the (strong) reachable sets of the semilinear evolution equation systems x′(t) + A(t)x(t) = f(t, x(t), u(t)) + Hu(t), x′(t) + A(t)x(t) = f(t, x(t), Hu(t)) + Hu(t) on a Banach space, and their corresponding linear systems are studied. Compared with previous results, the systems considered here are more general (f is not independent of the control u), no compactness assumptions on A or f are imposed in some of our main results, and we suppose f is a set-contraction rather than Lipschitz and have less restriction on the contraction coefficient. Other kinds of conditions are involved to guarantee the approximate controllability.     

带有阻尼项的偏泛函微分方程解的振动性

本文研究带有阻尼项的双曲型时滞偏微分方程 2 t2 u(x,t) +m(t) u t=a(t)△ u(x,t) +b(t)△ u(x,ρ(t) ) -q(t) f (u(x,σ(t) ) ,(x,t)∈ G≡Ω× R+ (1 )其中 ,R+=[0 ,+∞ ) ,Ω是一个具有逐段光滑边界的有界区域 .利用平均法和微分不等式方法得到方程 (1 )的若干新的振动准则 .     

On existence of positive periodic solutions of a kind of Rayleigh equation with a deviating argument

The existence of positive periodic solutions for a kind of Rayleigh equation with a deviating argument

一类具分布时滞的微分方程的正周期解的存在性与多解性

讨论具分布时滞的微分方程x′(t)=-a(t,x)x(t)+∫-0τf(t,r,x(t+r))dr,x′(t)=a(t,x)x(t)-∫0-τf(t,r,x(t+r))drx′(t)=-g(t,x(t))+∫0-τf(t,r,x(t+r))dr,x′(t)=g(t,x(t))-∫0-τf(t,r,x(t+r))dr正周期解问题,利用锥不动点定理,获得了这类问题正解存在性和多重性的充分条件,推广了已有文献的相关结果.     

Existence of Periodic Solutions About One Class Differential Equation

We discuss the existence and the number of periodic solutions of differential equation dx/dt=A1(t)x A2(t)x^2 A3(t)x^3/α0(t） α1(t)x α2(t)x^2 (1)where Ai（t），αj(t)(i=1,2,3;j=0,1,2) are continuous periodic functions.The results of this paper ex-tend the work of paper[1].     

有关Sturm—Liouville条件下的四阶奇异边值问题正解的研究

获得如下四阶奇异边值问题{u^（4）（t）-λh（t）f（t,u（t））=0,t∈（0,1）,u（0）=u（1）=0,αu^·（0）-βu^·（0）=γu^·（1）＋δu^·（1）=0,正解的存在性定理，其中α,β,γ,δ≥0,α＋β＞0,δ＋γ＞0,ρ=αγ＋γβ＋δα＞0,参数λ＞0，h（t）∈C（0,1）and f∈（（0,1）×（0,＋∞））文中主要应用全连续算子的逼近技巧和延拓定理以及不动点指数理论．     

一类非线性m-点边值问题正解的存在性

设α∈C[0,1],b∈C([0,1],(-∞,0)).设φ(t)为线性边值问题 u″+a(t)u′+b(t)u=0, u′(0)=0,u(1)=1的唯一正解.本文研究非线性二阶常微分方程m-点边值问题 u″+a(t)u′+b(t)u+h(t)f(u)=0, u′(0)=0,u(1)-sum from i=1 to(m-2)((a_i)u(ξ_i))=0正解的存在性.其中ξ_i∈(0,1),a_i∈(0,∞)为满足∑_(i=1)~(m-2)a_iφ_1(ξ_i)<1的常数,i∈{1,…,m-2}.通过运用锥上的不动点定理,在f超线性增长或次线性增长的前提下证明了正解的存在性结果.