Banach空间中渐近非扩张映象的带误差的修正的Ishikawa与Mann迭代程序

设E是满足Opial条件的一致凸Banach空间,C是E的一非空闭凸子集,T:C→C是渐近非扩张映象.又设对任给的x1∈C,序列{xn}由下列带误差的修正的Ishikawa迭代程序生成:其中, 是C中的序列,使得 且数列 满足下列条件(i)和(ii)之一: (i)tn∈[a,b]且sn∈[O,b];(ii)tn∈[a,b]且sn∈[a,b],这里,常数a,b满足0相似文献   

广义Lipschitz多值渐近Ф-半压缩映象不动点集的迭代程序

设K是实Banach空间E中的有界邻近子集，多值映象T1，T2：K→2^K是广义一致L—Lipschitz的渐近乒半压缩映象，且T1一致连续．证明了具误差的Ishikawa型迭代集合序列强收敛到T1，T2的公共不动点集．同时，证明了当T：K→2置是一致连续的广义Lipschitz强增生算子时，具误差的Ishikawa型迭代列强收敛到方程Tx=f的解．     

关于渐近非扩张映象不动点迭代的一点注记

设E是一致凸Banach空间,C是E的非空闭凸子集,T:C→C是具有不动点的渐近非扩张映象．该文证明了在某些适当的条件下,由下列修改了的Ishikawa迭代程序所定义的序列{xn}=xn 1=rpn,pn=(1-an)xn anTmn ryn un,yn=(1-bn)xn bnTkn xn vn, (n≥1)弱收敛到t的不动点．     

广义Lipschitz多值渐近Φ-半压缩映象不动点集的迭代程序

设K是实Banach空间E中的有界邻近子集,多值映象T1,T2:K→2K是广义一致L-L ipsch itz的渐近Φ-半压缩映象,且T1一致连续.证明了具误差的Ish ikaw a型迭代集合序列强收敛到T1,T2的公共不动点集.同时,证明了当T:K→2K是一致连续的广义L ipsch itz强增生算子时,具误差的Ish ikaw a型迭代列强收敛到方程Tx=f的解.     

Banach空间中渐近非扩张映象具误差的强收敛定理

设E是一实的Banach空间,其范数是一致Gteaux可微的;D是E的一非空闭凸子集,设T:D→D是具有序列{k_n}[1,∞),lim_(n→∞) k_n=1的渐近非扩张映象.本文证明了,在一定条件下,由(1.3)和(1.5)式定义的具误差的迭代序列{x_n}强收敛于T的不动点.本文结果也推广和改进了最近一些人的最新结果.     

一致等度连续的渐近拟伪压缩型映象的强收敛性

设E是实赋范线性空间.K是E中的非空凸子集.T1,T2是K上的自映象.当T1是一致等度连续的渐近拟伪压缩型映象,T2是广义一致Lipschitz映象时,研究了具误差的Isikawa型迭代序列强收敛于T1,T2公共不动点的充要条件.所得结果推广和改进了近期内的相应结果.     

赋范空间中渐近伪压缩映象不动点的迭代逼近

设x是赋范线性空间，D是x的非空子集．设T：D→x是一个一致L—Lipschitz的渐近伪压缩映象，F(T)表T的不动点集且F(T)非空．在迭代参数(αn)和(βn)的适当假设下，证明了修改了的具有误差项的Ishikawa和Mann迭代过程强收敛于T的不动点q．几个相关结果处理赋范空间中渐近非扩张映象不动点的迭代逼近问题．所得结果改进和推广了Chang，Park和Cho，Geobel和Kirl，Liu以及Schu等人的相关结果．     

关于非扩张映象的不动点逼近的Ishikawa迭代程序

设E是一致凸Banach空间,满足Opial条件或具有Frechet可微范数.又设C是E的有界闭凸子集.若T:C→C是非扩张映象,则对任给的初始数据x₀∈C,由Ishikawa迭代程序x_n+1=t_nT(s_nTx_n+(1-s_n)x_n)+(1-t_n)x_n,n≥0,定义的序列{x_n}弱收敛到T的     

非自渐近非扩张映象的Reich-Takahashi型迭代法的强收敛定理

设E是一实的Banach空间,其范数是一致Gteaux可微的;D是E的非空闭凸子集而且是E的非扩张收缩核.设T:D→E是具有序列{kn}[1,∞),limn→∞kn=1的非自渐近非扩张映象,P:E→D是一非扩张保核收缩.本文证明了,在一定条件下,由修正的Reich-Takahashi迭代法(1.2)和(1.3)式定义的迭代序列{xn}强收敛于非自渐近非扩张映象T的不动点.     

关于渐近伪压缩型映象的不动点的迭代构造

本文引入了Banach空间中一类渐近伪压缩型映象,它概括了熟知的若干映象类成特例.而且,还研究了关于这类映象的带误差的修改了的Ishikawa与Mann迭代序列的逼近问题.本文所得结果改进与推广了张石生教授的所有结果以及前人研究的相应结果.     

Numerical Measure of a Complex Matrix

We introduce a natural probability measure over the numerical range of a complex matrix A ∈ M _n( \input amssym $\Bbb C$ ). This numerical measure μ_A can be defined as the law of the random variable 〈AX, X〉 ∈ \input amssym $\Bbb C$ when the vector X ∈ \input amssym $\Bbb C$ ⁿ is uniformly distributed on the unit sphere. If the matrix A is normal, we show that μ_A has a piecewise polynomial density f_A, which can be identified with a multivariate B‐spline. In the general (nonnormal) case, we relate the Radon transform of μ_A to the spectrum of a family of Hermitian matrices, and we deduce an explicit representation formula for the numerical density that is appropriate for theoretical and computational purposes. As an application, we show that the density f_A is polynomial in some regions of the complex plane that can be characterized geometrically, and we recover some known results about lacunae of symmetric hyperbolic systems in 2 + 1 dimensions. Finally, we prove under general assumptions that the numerical measure of a matrix A ∈ M _n (\input amssym $\Bbb C$ ) concentrates to a Dirac mass as the size n goes to infinity. © 2011 Wiley Periodicals, Inc.     

The behaviour of microstructures with small shears of the austenite-martensite interface in martensitic phase transformations

Let $\Omega \subset \Bbb{R}^2$ denote a bounded domain whose boundary $\partial \Omega$ is Lipschitz and contains a segment $\Gamma_0$ representing the austenite-twinned martensite interface. We prove $$\displaystyle{\inf_{{u\in \cal W}(\Omega)} \int_\Omega \varphi(\nabla u(x,y))dxdy=0}$$ for any elastic energy density $\varphi : \Bbb{R}^2 \rightarrow [0,\infty)$ such that $\varphi(0,\pm 1)=0$. Here ${\cal W}(\Omega)$ consists of all Lipschitz functions $u$ with $u=0$ on $\Gamma_0$ and $|u_y|=1$ a.e. Apart from the trivial case $\Gamma_0 \subset \reel \times \{a\},~a\in \Bbb{R}$, this result is obtained through the construction of suitable minimizing sequences which differ substantially for vertical and non-vertical segments.     

Boundary Values of Generalized Harmonic Functions Associated with the Rank-One Dunkl Operator

We consider the local boundary values of generalized harmonic functions associated with the rank-one Dunkl operator $D$ in the upper half-plane $R^{2}_+=R\times(0,\infty)$, where $$(Df)(x)=f'(x)+(\lambda/x)[f(x)-f(-x)]$$ for given $\lambda\ge0$. A $C^2$ function $u$ in $R^{2}_+$ is said to be $\lambda$-harmonic if $(D_x^2+\partial_{y}^2)u=0$. For a $\lambda$-harmonic function $u$ in $R^{2}_+$ and for a subset $E$ of $\partial R^{2}_+=R$ symmetric about $y$-axis, we prove that the following three assertions are equivalent: (i) $u$ has a finite non-tangential limit at $(x,0)$ for a.e. $x\in E$; (ii) $u$ is non-tangentially bounded for a.e. $x\in E$; (iii) $(Su)(x)<\infty$ for a.e. $x\in E$, where $S$ is a Lusin-type area integral associated with the Dunkl operator $D$.     

和图、整和图与模和图的几个结果

Let N denote the set of positive integers. The sum graph G^＋（S） of a finite subset S belong to N is the graph （S, E） with uv ∈ E if and only if u ＋ v ∈ S. A graph G is said to be a sum graph if it is isomorphic to the sum graph of some S belong to N. By using the set Z of all integers instead of N, we obtain the definition of the integral sum graph. A graph G = （V, E） is a mod sum graph if there exists a positive integer z and a labelling, λ, of the vertices of G with distinct elements from {0, 1, 2,..., z - 1} so that uv ∈ E if and only if the sum, modulo z, of the labels assigned to u and v is the label of a vertex of G. In this paper, we prove that flower tree is integral sum graph. We prove that Dutch m-wind-mill （Dm） is integral sum graph and mod sum graph, and give the sum number of Dm.     

Banach空间中有限个增生算子公共零点的带误差项的迭代逼近

令E为实一致凸Banach空间,满足Opial条件或其范数是Frechet可微的.令为增生算子,满足值域条件且为非空闭凸子集且满足 .将引入新的带误差项的迭代算法并证明迭代序列弱收敛于{Ai}ki=1的公共零点.     

Shift Generated Haar Spaces on Compact Domains in the Complex Plane

Haar spaces are certain finite-dimensional subspaces of $\cc(K)$, where $K$ is a compact set and $\cc(K)$ is the Banach space of continuous functions defined on $K$ having values in $\C$. We characterize those Haar spaces which are generated by shifts applied to a single, analytic function for $K\subset\C$. This means that an arbitrary finite number of shifts generates Haar spaces by forming linear hulls. We have to distinguish two cases: (a) $K\not=\overline{K^\circ}$; (b) $K=\overline{K^\circ}$. It turns out that, in case (a), an analytic Haar space generator for dimensions one and two is already a universal Haar space generator for all dimensions. The geometrically simplest case that, in case (b), $K$ is convex with smooth boundary turns out to be the most difficult case. There is one numerical example in which the entire function $f:=1/\Gamma$ is interpolated in a shift generated Haar space of dimension four.     

一类非线性悬臂梁方程正解的存在性与多解性

研究了非线性四阶常微分方程u(4)(t)=f(t,u(t),u'(t)),t ∈[0,1]\E在边界条件u(0)=u'(0)=u"(1)=u"'(1)=0下的正解,其中E(∩)[0,1]是一个零测度的闭集,而非线性项,(t,u,u)可以在t∈E时奇异.通过构造适当的积分方程并利用锥上的不动点定理证明了这个方程在满足与n有关的条件下存在n个正解,其中n是某个自然数.     

Banach空间中非扩张映象不动点的黏性逼近

设E是一致光滑的Banach空间,其范数是一致Gateaux可微的;设C是E之一非空闭凸子集,f:C→C是压缩映象,T:C→C是非扩张映象.本文用黏性逼近方法证明了在较一般的条件下,由(1.6)式定义的迭代序列{x_n)的强收敛性.本文推广和改进了一些近期结果.     

Distance Sets of Well-Distributed Planar Point Sets

We prove that a well-distributed subset of ${\Bbb R}^2$ can have a distance set $\Delta$ with $\#(\Delta\cap [0,N])\leq CN^{3/2-\epsilon}$ only if the distance is induced by a polygon $K$. Furthermore, if the above estimate holds with $\epsilon=\frac12$, then $K$ can have only finitely many sides.     

Improved Approximation Algorithms for Geometric Set Cover

Given a collection S of subsets of some set and the set cover problem is to find the smallest subcollection that covers that is, where denotes We assume of course that S covers While the general problem is NP-hard to solve, even approximately, here we consider some geometric special cases, where usually Combining previously known techniques [4], [5], we show that polynomial-time approximation algorithms with provable performance exist, under a certain general condition: that for a random subset and nondecreasing function f(·), there is a decomposition of the complement into an expected at most f(|R|) regions, each region of a particular simple form. Under this condition, a cover of size O(f(|C|)) can be found in polynomial time. Using this result, and combinatorial geometry results implying bounding functions f(c) that are nearly linear, we obtain o(log c) approximation algorithms for covering by fat triangles, by pseudo-disks, by a family of fat objects, and others. Similarly, constant-factor approximations follow for similar-sized fat triangles and fat objects, and for fat wedges. With more work, we obtain constant-factor approximation algorithms for covering by unit cubes in and for guarding an x-monotone polygonal chain.