EXISTENCE OF PERIODIC SOLUTIONS TO A KIND OF HIGHER ORDER FUNCTIONAL DIFFERENTIAL EQUATION WITH TWO DEVIATING ARGUMENTS

In this paper, by the theory of Fourier series, Bernoulli number theory and continu-ation theorem of coincidence degree theory, we study a kind of higher order functional differential equation with two deviating arguments. Some new results on the existence of periodic solutions are obtained.     

Banach空间二阶非线性奇异微分方程的解

文中讨论了Banach空间中一类右端具有奇异性的二阶非线性微分方程的边值问题,利用不动点方法,获得了该边值问题解的存在性定理.最后还给出了相应的例子.     

四阶非线性特征值问题的正解

本文考虑了四阶非线性特征值问题d4u/dt4=λg(t)f(u,u″),0＜t＜1,u(0)=u(1)=0,au″(0)-bu″′(0)=0,cu″(1)+du″′(1)=0.其中g(t)∈C((0,1),[0,∞)),f(u,v)∈C([0,∞)×(-∞,0],[0,∞)),a≥0,b≥0,c ≥0,d ≥ 0,且△=ac+ad+bc＞0.利用锥压缩与拉伸不动点定理,获得了上述问题正解的存在性结果.     

Hybrid approaches to attribute reduction based on indiscernibility and discernibility relation

Attribute reduction is one of the key issues in rough set theory. Many heuristic attribute reduction algorithms such as positive-region reduction, information entropy reduction and discernibility matrix reduction have been proposed. However, these methods are usually computationally time-consuming for large data. Moreover, a single attribute significance measure is not good for more attributes with the same greatest value. To overcome these shortcomings, we first introduce a counting sort algorithm with time complexity O(∣C∣ ∣U∣) for dealing with redundant and inconsistent data in a decision table and computing positive regions and core attributes (∣C∣ and ∣U∣ denote the cardinalities of condition attributes and objects set, respectively). Then, hybrid attribute measures are constructed which reflect the significance of an attribute in positive regions and boundary regions. Finally, hybrid approaches to attribute reduction based on indiscernibility and discernibility relation are proposed with time complexity no more than max(O(∣C∣²∣U/C∣), O(∣C∣∣U∣)), in which ∣U/C∣ denotes the cardinality of the equivalence classes set U/C. The experimental results show that these proposed hybrid algorithms are effective and feasible for large data.     

Banach空间中二阶微分方程的周期边值问题

本文在Banach空间中研究了二阶非线性微分方程的周期边值问题:-u″=f(t,u),u(0)= u(2π),u′(0)=u′,(2π)在上下解反向给定时,利用半序理论和新的比较原理,证明了该周期边值问题最小解和最大解的存在性,解的唯—性,并给出了唯一解的近似迭代序列的误差估计式．     

Banach空间中非线性奇异两点边值问题的多重正解

本文研究Banach空间E中非线性奇异边值问题-x'=f(t,x), t∈(0,1), a₁x(0)-a₂x'(0)=θ, b₁x(0)-b₂x'(1)=θ.其中θ是E中的零元素, f({t,x})在端点t=0和t=1处具有奇性. 利用不动点定理获得了该问题至少有两个正解的结果.     

连续偏序集及其Smyth幂的几个等权定理

推广连续D om a in的权的概念到连续偏序集上,探讨连续偏序集的权、相应内蕴拓扑的权、定向完备化的权以及Sm yth幂D om a in的权间的关系。得到了几个等权定理:(1)连续偏序集的权与其上Scott拓扑、L aw son拓扑的权相等;(2)连续偏序集的权与其定向完备化的权相等;(3)无穷连续D om a in的权与其Sm yth幂D om a in的权相等;(4)有限D om a in的权小于或等于它的Sm yth幂D om a in的权。     

Banach空间一阶微分方程终值问题的解

本文利用新的比较结果和半序理论研究Ｂａｎａｃｈ空间中一阶非线性微分方程终值问题的最小解和最大解的存在性,改进和推广了某些已知结果．     

Positive solutions of three-point boundary value problems for systems of nonlinear second order ordinary differential equations

In this paper, we study the three-point boundary value problems for systems of nonlinear second order ordinary differential equations of the form

Under some conditions, we show the existence and multiplicity of positive solutions of the above problem by applying the fixed point index theory in cones.