H-SPLITTINGS AND ASYNCHRONOUS PARALLELITERATIVE METHODS

1.PropertiesofH-splittingA.FrommerandD.B.Szyldl3]proposedH-splittingandH-compatiblesplittingfortwo--stagemethods.Buttheydidnotdiscusstwosplittingfurthermore.WewillshowsomepropertiesofH-splittingandH-compatiblesplittingbeforeweapplythemtoestablishasynchronousparallelmultisplittingalgorithm.Definition1.([3])GivenAEL(R"),A=M--N(M,NEL(R")),whichitcalledH--splitting,if(M)--INIisanM-matrix;whichiscalledH-compati4le.SPlitting:if(A)=(M)--INI.Where(A)isO8trowskimatrix,INIisabsolutionma…     

关于伪压缩映象不动点迭代的一点注记

设$K$是自反的并且具有一致Gateaux可微范数的Banach空间$E$的非空有界闭凸子集.设$T:K\rightarrow K$是一致连续的伪压缩映象.假设$K$的每一非空有界闭凸子集对非扩张映象具有不动点性质.设$\{\lambda_n\}$是$(0,\frac{1}{2}]$中序列满足: (i) $\lim_{n\rightarrow \infty}\lambda_n=0$; (ii) $\sum_{n=0}^{\infty}\lambda_n=\infty$.任给$x_1\in K$,定义迭代序列$\{x_n\}$为:$x_{n+1}=(1-\lambda_n)x_n+\lambda_nTx_n-\lambda_n(x_n-x_1),n\geq 1.$若$\lim_{n\rightarrow \infty}\|x_n-Tx_n\|=0$, 则上述迭代产生的$\{x_n\}$强收敛到$T$的不动点.     

Optimum Modified Extrapolated Jacobi Method for Consistently Ordered Matrices

1.IlltroductionandPreliminariesWeconsiderthelineaxsystemAx=b,(1.1)wheteAERn,",bERnanddet(A)/O.WeaJ8oassumethatAhasthef0rmwhereA11,A22axesquarenonsingular(usuallydiagonal)matrices-Asisknow[61,AisaconSisentlyordered2-cyclicmatris.Forsolving(1.1)weintendtousethef0lfowngsimpleiterativemethod:In(1.4)and(1.6),w1,w2arenonzeroparameters(extraP0lati0nparameters)andI1,I2areidelltitymatricesofthesamesizesasA11anA22respectively.Theconstructionofmeth0d(1.3)isbasedonthesplittingA=M-N,whereM=Dfl-1…     

A New Class AOR Preconditioner for $L$-Matrices

Hadjidimos(1978) proposed a classical accelerated overrelaxation(AOR) iterative method to solve the system of linear equations, and discussed its convergence under the conditions that the coefficient matrices are irreducible diagonal dominant, L-matrices, and consistently orders matrices. Several preconditioned AOR methods have been proposed to solve system of linear equations Ax = b, where A ∈ R~(n×n) is an L-matrix. In this work, we introduce a new class preconditioners for solving linear systems and give a comparison result and some convergence result for this class of preconditioners. Numerical results for corresponding preconditioned GMRES methods are given to illustrate the theoretical results.     

Fast Parallel Algorithms for Computing Generalized Inverses $A^+$ and $A_{MN}^+$

The parallel arithmetic complexities for computing generalized inverse $A^+$, computing the minimum-norm least-squares solution of $Ax=b$, computing order $m+n-r$ determinants and finding the characteristic polynomials of order $m+n-r$ matrices are shown to have the same grawth rate. Algorithms are given that compute $A^+$ and $A_{MN}^+$ in $O(\log r\dot \log n+\log m)$ and $O(\log^2n+\log m)$ steps using a number of processors which is a polynomial in $m, \ n$ and $r$ $(A\in B_r^{m\times n},r=rank \ A)$.     

Banach空间中伪压缩映象不动点的迭代逼近

Let K be a nonempty closed convex subset of a real p-uniformly convex Banach space E and T be a Lipschitz pseudocontractive self-mapping of K with F（T） ：= {x ∈ K：Tx=x}≠φ. Let a sequence {xn} be generated from x1 ∈ K by xn＋1 = anxn,＋ bnTyn＋＋ cnun, yn= a′nxn~ ＋ b′nTx,＋ c′n,un, for all integers n ≥ 1. Then ‖xn - Txn,‖ → 0 as n→∞. Moreover, if T is completely continuous, then {xn} converges strongly to a fixed point of T.     

THE NECESSARV AND SUFFICIENT CONDITIONS FOR LIPSCHITZ LOCAL HOMEOMORPHISM

For a locally Lipschitz map f:$R^{n}\rightarrow R^{n}$,the well known inverse functin theorem gives a sufficient condition for f to be a Lipschitz local homeomorphims at a point $x_{0}$,that is,$\partial f(x_{0}$ is invertible.In this paper,it is showed that this condition is not necessary and some necessary and sufficient conditions are given.     

On the Number of Zeroes of Exponential Systems

A system $E:C^n\rightarrow C^n$ is said to be an exponential one if its terms are $ae^{im_1Z_1}.\cdots .e^{im_nZ_n}$. This paper proves that for almost every exponential system $E:C^n\rightarrow C^n$ with degree $(q_1,\cdots,q_n)$, $E$ has exactly $\Pi^n_j=1(2q_j)$ zeroes in the domain $D=\{(Z_1,\cdots,Z_n)\in C^n:Z_j=x_j+iy_j,x_j,y_j\in R,0\leq x_j<2\pi ,j=1,\cdots,n\}$, and all these zeroes can be located with the homotopy method.     

关于广义{\Phi}-增生算子的最速下降法的收敛定理

设$E$为一致光滑Banach空间,$A:E\to E$为有界次连续广义${\it \Phi} $-增生算子满足:对任意$x_0\in E$,选取$m\ge 1$,使得$\| x_0 - x^* \| \le m$且$\mathop {\underline {\lim } }\limits_{r \to \infty } {\it \Phi} (r) > m\left\| {Ax_0 } \right\|$.设$\{C_n\}$为$[0,1]$中数列满足控制条件: i)$C_n\to 0\,(n\to\infty)$; ii)$\sum\limits_{n = 0}^\infty {C_n } = \infty $.设$\{x_n\}_{n\ge0}$由下式产生x_{n + 1} = x_n - C_n Ax_n ,\q n \ge 0, \eqno{(@)}$$则存在常数$a>0$,当$C_n < a$时,$\{x_n\}$强收敛于$A$的唯一零点$x^{*}$.     

自反Banach空间中非扩张非自映射的粘滞迭代逼近方法

主要在自反和严格凸的且具有一致G(a)teaux可微范数的Banach空间中研究了非扩张非自映射的粘滞迭代逼近过程,证明了此映射的隐格式与显格式粘滞迭代序列均强收敛到它的某个不动点.     

Tame sets, dominating maps, and complex tori

A discrete subset of is said to be tame if there is an automorphism of taking the given discrete subset to a subset of a complex line; such tame sets are known to allow interpolation by automorphisms. We give here a fairly general sufficient condition for a discrete set to be tame. In a related direction, we show that for certain discrete sets in there is an injective holomorphic map from into itself whose image avoids an -neighborhood of the discrete set. Among other things, this is used to show that, given any complex -torus and any finite set in this torus, there exist an open set containing the finite set and a locally biholomorphic map from into the complement of this open set.

     

TYPE K MONOTONE SYSTEMS WITH AN ORDER-INCREASING INVARIANT FUNCTION

51.IntroductionBeginingwiththepath-breakingworkofM.W.HirschI1-4]forcooperativesystemsandmonotonesemiflows,thereisnowanextensiveliteratureoncooperativesystemsandmoncatonedynamicalsystems.Assumingthatthesystemiscooperativeandirreducible,HirschshowedthataImosteveryforwardorbitwithcompactclosure,inthesenseofLebesguemeasure,tendstoequilibriaast- oc(see2,Theorem4.l]).Asimilarresultholdsforastronglymonotonesemifiowonastronglyorderspace(see[4,Theoremo.1]).Manypeoplehavegivensomeadditionalconditio…     

On the Necessary and Sufficient Condition of the Local Optimal Solution of Quadratic Programming

In this paper a necessary and sufficient aptimality condition of quadratic programming is giver. The main result is Theorem 3.1. It is shown that a point x_0 is local optimal solution of quadratic programming (1, l)if and only if x_0 is a Kuhn-Tu cker point and h^Tch is non-negative for every point im{h|a^T_jh=0,j\in J^*,a^T_jh \leq 0,j\in J_1\J^*}.     

Monotone Convergence of Iterative Methods for Singular Linear Systems

In this paper, monotonicity of iterative methods for solving general solvable singularly systems is discussed. The monotonicity results given by Berman, Plemmons, and Semal are generalized to singular systems. It is shown that for an iterative method introduced by a nonnegative splitting of the coefficient matrix there exist some initial guesses such that the iterative sequence converges towards a solution of the system from below or from above. The monotonicity of the block Gauss-Seidel method for solving a p-cyclic system and Markov chain is considered.     

解一般矩阵方程的GPBiCG(m,l)法

The generalized product bi-conjugate gradient(GPBiCG(m,l))method has been recently proposed as a hybrid variant of the GPBi CG and the Bi CGSTAB methods to solve the linear system Ax=b with non-symmetric coefficient matrix,and its attractive convergence behavior has been authenticated in many numerical experiments.By means of the Kronecker product and the vectorization operator,this paper aims to develop the GPBi CG(m,l)method to solve the general matrix equation■ and the general discrete-time periodic matrix equations■ which include the well-known Lyapunov,Stein,and Sylvester matrix equations that arise in a wide variety of applications in engineering,communications and scientific computations.The accuracy and efficiency of the extended GPBi CG(m,l)method assessed against some existing iterative methods are illustrated by several numerical experiments.     

Hilbert $C^*$-模算子代数上Lie三重导子的刻画

假设$\mathcal A$是一个含单位元$e$的交换$C^*$-代数, $\mathcal M$是一个满的Hilbert $\mathcal A$-模. 令End_{$\mathcal A$}($\mathcal M$)表示$\mathcal M$上的全体有界$\mathcal A$线性算子构成的代数, $\mathcal M''$M表示$\mathcal M$到$\mathcal A$的全体有界$\mathcal A$线性映射构成的集合. 在本文中, 我们证明了如果存在$\mathcal M$中元素$x_0$和$\mathcal M''$中的元素$f_0$满足$f_0(x_0)=e$, 那么End_{$\mathcal A$}($\mathcal M$)上的$\mathcal A$-线性Lie三重导子都是标准的.     

超凸度量空间中非扩张映象不动点的逼近

研究了超凸度量空间中非扩张映象不动点的逼近问题,得到了具误差的Ishikawa迭代序列收敛到不动点的一个充要条件．     

Two Error Bounds for Constrained Optimization Problems and Their Applications

This paper presents a global error bound for the projected gradient and a local error bound for the distance from a feasible solution to the optimal solution set of a nonlinear programming problem by using some characteristic quantities such as value function, trust region radius etc., which are appeared in the trust region method. As applications of these error bounds, we obtain sufficient conditions under which a sequence of feasible solutions converges to a stationary point or to an optimal solution, respectively, and a necessary and sufficient condition under which a sequence of feasible solutions converges to a Kuhn–Tucker point. Other applications involve finite termination of a sequence of feasible solutions. For general optimization problems, when the optimal solution set is generalized non-degenerate or gives generalized weak sharp minima, we give a necessary and sufficient condition for a sequence of feasible solutions to terminate finitely at a Kuhn–Tucker point, and a  sufficient condition which guarantees that a sequence of feasible solutions terminates finitely at a stationary point. This research was supported by the National Natural Science Foundation of China (10571106) and CityU Strategic Research Grant.     

A splitting method for quadratic programming problem

1. IntroductionThe quadratic programming (QP) problem is the most simple one in nonlinear pro-gramming and plays a very important role in optimization theory and applications.It is well known that matriX splitting teChniques are widely used for solving large-scalelinear system of equations very successfully. These algorithms generate an infinite sequence,in contrast to the direct algorithms which terminate in a finite number of steps. However,iterative algorithms are considerable simpler tha…     

On some optimal control problems connected with the Navier-Stokes system

We consider problems of the form $$\left\{ \begin{gathered} J(y) \to \inf : \hfill \\ L(y) = u, \left\| u \right\| \leqslant M, y(0) = 0, y(T) = v, \hfill \\\end{gathered} \right.$$ whereL is the operator of the Navier-Stokes system. We obtain theorems for existence of a solution and necessary and sufficient conditions for an extremum. We also study the uniqueness of the solution and construct the asymptotics of the solution in terms of the parameter M. Bibliography: 11 titles.