Banach空间中有限个增生算子公共零点的迭代强收敛定理

令E为实自反Banach空间具一致Gteaux可微范数,AiE×E(i=1,2,…,k)为增生算子且满足∩ki=1Ai-1(0)≠φ.令C为E的非空闭凸子集并满足■C∩r>0R(I+rAi),i=1,2,…,k.将引入一种带误差项的迭代算法,并证明迭代序列强收敛于{Ai}ki=1的公共零点.     

求解广义互补问题

1 引言 设为一闭凸锥,f是R~n到自身的一映射.广义互补问题,记作GCP(K,f),即找一向量x满足 GCP(K,f) x∈K,f(x)∈且x~Tf(x)=0,(1) 其中,是K的对偶锥(即对任一K中向量x,满足x~Ty≤0的所有y的集合).该问题首先 由Habetler和Price提出.当K=R_+~n(R~n空间的正卦限),此问题就是一般的互补问题.许多作者已经提出了很多求解线性或非线性互补问题的方法.例如:Dafermos,Fukushima,Harker和Price以及其它如参考文献所列.近年来,何针对单调线性变分不等式提出了一些投影收缩算法. Fang在函数是Lipschitz连续及强单调的条件下,在[3]给出一简单的迭代投影法,在[4]中给出一线性化方法去求解广义互补问题(1).在[3]中,他的迭代模式是     

Banach空间中有限个增生算子公共零点的带误差的迭代格式

本文研究了有限个增生算子公共零点的迭代构造,利用非扩展保核收缩映射的性质,在满足Opial条件或其范数是Frech閠可微的实一致凸Banach空间中,获得上迭代序列弱收敛于有限个增生算子公共零点的结论.对单个增生算子推广到了有限个的情形.     

一类广义线性变分不等式的求解与应用

数学规划中的某些问题等价于如下形式的广义线性变分不等式:确定向量u^*,使其满足 Nu*+t∈Ω(v-(Nu*+t))~T(Mu*+q)≥0>O,v∈Ω.就此给出了求解一类广义线性变分不等式的迭代方法,它们可以用来求解一类更有实用价值的广义规划.     

复值度量空间上满足分式收缩条件的映射族的唯一公共不动点

指出了文献[Int.J.Pure Appl.Math.,2011,73(2):159-164]中给出的定理的错误证明,得出复值度量空间上满足分式收缩条件的四个映射的唯一公共不动点定理,并给出了若干更一般形式的结论及不动点定理.所得结论推广和改进了一些已知结果.     

度量空间上具有变系数的收缩条件的两个集值映射的公共不动点

在完备的度量空间上利用满足具有某种变系数的收缩条件或φ-收缩条件的两个集值映射构造了一个收敛序列,然后证明了该序列的唯一极限就是两个映射的公共不动点并给出了映射族存在唯一公共不动点的充分条件,同时给出了几个特殊结果.所得结果推广和改进了一些已有的结论.     

关于Hamilton3-正则2-连通平面图的一个注记

设Fk*是满足以下条件的3-正则2-连通平面图G所组成的图类,在G中存在这样的圈C,使得G-E(C)产生k个不相交的树T1,…,Tk(|E(Ti)|≥3,i=1,…,k),且这些树是按C的指定方向C*依次粘在圈C上的．本文主要证明了如下结果:Fk*中的图都是Hamilton的．     

拓扑空间的收缩核与半收缩核(英)

本文的主要目的是建立收缩核与近似连续之间的联系，基于半连续函数概念，我们构造了一类收缩核，得到了关于这一概念的许多的性质与例子，证明并解释了半收缩核与拓扑折送之间的关系。     

拓扑空间的收缩核与半收缩核

本文的主要目的是建立收缩核与近似连续之间的联系，基于半连续函数概念，我们构造了一类收缩核，得到了关于这一概念的许多的性质与例子，证明并解释了半收缩核与拓扑折迭之间的关系。     

Banach空间非扩张映像不动点强收敛定理

设E是具弱序列连续对偶映像自反Banach空间, C是E中闭凸集, T:C→ C是具非空不动点集F(T)的非扩张映像.给定u∈ C,对任意初值x0∈ C,实数列{αn}n∞=0,{βn}∞n=0∈ (0,1),满足如下条件:(i)sum from n=α to ∞α_n=∞, α_n→0;(ii)β_n∈[0,α) for some α∈(0,1);(iii)sun for n=α to ∞|α_(n-1) α_n|<∞,sum from n=α|β_(n-1)-β_n|<∞设{x_n}_(n_1)~∞是由下式定义的迭代序列:{y_n=β_nx_n (1-β_n)Tx_n x_(n 1)=α_nu (1-α_n)y_n Then {x_n}_(n=1)~∞则{x_n}_(n=1)~∞强收敛于T的某不动点.     

Renorms and topological linear contractions on Hilbert spaces

Properties of and the relationships between (topological) proper contractions, (topological) strict contractions and (topological) contractions are investigated. Explicit renorms are constructed so that all operators in a (finite or countable) family or a semigroup simultaneously become proper contractions or strict contractions. Some results are obtained for operator weighted shifts or operator weighted continuous shifts to be topological strict contractions. Project supported by the Chinese University of Hong Kong (Grant No. 2060144) and NSERC of Canada (Grant No. A8096).     

Divisorial Contractions in Dimension Three which Contract Divisors to Compound A 1 Points

We deal with a divisorial contraction in dimension three which contracts its exceptional divisor to a compound A ₁ point. We prove that any such contraction is obtained by a suitable weighted blow-up.     

Joint extensions in families of contractive commuting operator tuples

In this paper we systematically study extension questions in families of commuting operator tuples that are associated with the unit ball in Cd.     

Fixed Point Curve for Weakly Inward Contractions and Approximate Fixed Point Property

In this paper, we discuss the concept of fixed point curve for linear interpolations of weakly inward contractions and establish necessary condition for a nonex- pansive mapping to have approximate fixed point property.     

Classification of extremal contractions from smooth fourfolds of -type

We investigate divisorial contractions of extremal rays from
smooth fourfolds. When the exceptional divisor is contracted to a curve, we prove that the divisor is a -bundle or quadric bundle over a smooth curve and the contraction is the blowing up along the curve. Furthermore we determine the local analytic structure of the contraction.

     

General elephants of three-fold divisorial contractions

We treat three-fold divisorial contractions whose exceptional divisors contract to Gorenstein points. We prove that a general element in the anti-canonical system around the exceptional divisor has at worst Du Val singularities. As application to classification, we describe divisorial contractions to compound points, and moreover, we deduce that any divisorial contraction to a compound or point has discrepancy .

     

A definitive result on asymptotic contractions

We generalize a fixed point theorem for asymptotic contractions due to Kirk [W.A. Kirk, Fixed points of asymptotic contractions, J. Math. Anal. Appl. 277 (2003) 645-650]. Our result is the final generalization in some sense.     

The distance between fixed points of some pairs of maps in Banach spaces and applications to differential systems

Let T be a λ-contraction on a Banach space Y and let S be an almost λ-contraction, i.e. sum of an (ε, λ)-contraction with a continuous, bounded function which is less than ε in norm. According to the contraction principle, there is a unique element u in Y for which u = Tu: If moreover there exists v in Y with v = Sv, then we will give estimates for ‖u−v‖. Finally, we establish some inequalities related to the Cauchy problem.     

On a fixed point theorem of Kirk

W.A. Kirk [J. Math. Anal. Appl. 277 (2003) 645-650] first introduced the notion of asymptotic contractions and proved the fixed point theorem for this class of mappings. In this note we present a new short and simple proof of Kirk's theorem.