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1.
1IntroductionLetXbeacompactmetricspaceandfEC(X,X).ApointyEXiscalledanw--limitpointofxifthereexistm-cosuchthatf"i(x)-y.Letw(x)denotethesetofw-limitpointsofx.FOrasubsetYofX,defineA(Y)=Uw(x).LetAl=A(x)andforanyn>l,inductivelydefineA"=anYcoA(A"--').obviously,AlDAcDAsD''.ThesetA"=nA"willbecalled1theattractingcentreoff.WesaythatxEXisaperiodicpointoffwithperiodnifthereexistsn>0suchthatf"(x)=xbutf'(x)/x,15i5n--1.Ifn=Ithenxwillbecalledafixedpointoff.ApointxeXiscalledanon-wanderingpointo…  相似文献   

2.
一、选择题:   1.(理)复数1/i-2+1/1-2i的虚部为   A.1/5i B.1/5 C.-1/5i D.-1/5   (文)若集合M={x|x=cos nπ/2,n∈Z},则M的真子集个数是   A.3B.7C.15D.无穷多个   2.已知函数f(x)=2x+3,(x∈R), 若|f(x)-1|0),则a, b之间的关系是……  相似文献   

3.
1.IntroductionInthispaper,weconsiderthefollowingnonlinearprogr~ngproblemwherec(x)=(c,(x),c2(2),',We(.))',i(x)andci(x)(i=1,2,',m)arerealfunctions*ThisworkissupPOrtedbytheNationalNaturalScienceFOundationofChinaandtheManagement,DecisionandinformationSystemLab,theChineseAcademyofSciences.definedinD={xEReIISx5u}.Weassumethath相似文献   

4.
1 IntroductionIn the recent years, the existence problem of BVP of second order functionaldifferential equations of the forms[p(t)i(t)]' = f(t, xf, x(t)), (1)i(t) = f(t, x(t), x(al(t)),'', x(a.(t)), i(t)), (2)x(t) = f(t, x(t), x(al(t)),'', x(U.(t)), i(t), i(n(t)),'', i(fu(t))), (3)t -- r 5 al(t),D(t) 5 t, as 0 5 t 5 T,i = 1,2,'' Ink j = 1,2,'',m, subjectto some boundary value conditions have been considered by several authors(please see [1-4],[6] and the references therein). In these pa…  相似文献   

5.
边选 《中学数学》2003,(7):37-40
第 卷 (选择题共 6 0分 )一、选择题 :(本大题 1 2小题 ,每小题 5分 ,共 60分 .)1 . 1 - 3 i(3 +i) 2 =(   ) .(A) 14 +34 i  (B) - 14 - 34 i(C) 12 +32 i (D) - 12 - 32 i2 .已知 x∈ (- π2 ,0 ) ,cosx =45,则 tan2 x =(   ) .(A) 72 4   (B) - 72 4   (C) 2 47  (D) - 2 473.设函数 f (x) =2 -x - 1 ,x≤ 0 ,x1 2 ,   x >0 .若 f(x0 ) >1 ,则 x0 的取值范围是 (   ) .(A) (- 1 ,1 )    (B) (- 1 ,+∞ )(C) (-∞ ,- 2 )∪ (0 ,+∞ )(D) (-∞ ,- 1 )∪ (1 ,+∞ )4 . O是平面上一定点 ,A、B、C是平面上不共线的三个…  相似文献   

6.
一、选择题(5×12=60分)   1.复数1-2i/1+i=( )   A.1/2-3/2i B.-1/2+3/2i   C.-1/2-3/2i D.1/2+3/2i   2.若A={x∈Z|2≤2x≤8},B={x∈R||log2x|>1},则A∩CRB的元素个数为( )   ……  相似文献   

7.
洪绍方 《数学年刊A辑》2000,21(3):377-382
设f为一个算术函数,S={x 1,…,x n}为一个n元正整数集合.称S为gcd-封闭的, 如果对于任意1 i,j n,均有(x i,x j)∈S.以 ={y 1,…,y m}表示包含S的最小gcd-封闭的正整数集合. 设(f(x i,x j))表示一个n×n矩阵, 其(i,j)项为f在x i与x j的最大公因子(x i,x j)处的值. 设(f[x i,x j])表示一个n×n矩阵, 其(i,j)项为f在x i与x j的最小公倍数[x i.xj]处的值. 本文证明了: (i) 如果f∈C s ={f:(f*μ)(d)>0, x∈S,d|x},这里f*μ表示f与μ的Dirichlet乘积,μ表示M bius函数,那么 并且(1)取等号当且仅当S=;(ii)如果f为乘法函数,并且 ∈Cs,那么 并且(2)取等号当且仅当S= .不等式(1)和(2)分别改进了Bourque与Ligh在1993年和1995年所得到的结果.  相似文献   

8.
1IntroductionandResultConsiderthenonparametricmedianregressionlllodelwhereg:[0,1]-Risasmoothfunctiontobeestilllated.{xu,.15z57L}arelloll-ralldollldesignpointsintheinterval[0,1],{e,,i.15i相似文献   

9.
1 IntroductionLetΩ be a bounded domain in Rn and Ω be its boundary.ThenΣ =Ω× ( 0 ,1 ) is abounded domain in Rn+1 .We consider the following backwad problem of a prabolic equa-tion: u t= ni,j=1 xiaij( x) u xj -c( x) u,   ( x,t)∈Σ,( 1 )u| Ω× [0 ,1 ] =0 , ( 2 )u| t=1 =g( x) . ( 3 )   Where { aij( x) } are smooth functions given onΩ satisfyingaij( x) =aji( x) ,   1≤ i,j≤ n, ( 4)α0 ni=1ζ2i ≤ ni,j=1aij( x)ζiζj≤α1 ni=1ζ2i,   ζ∈ Rn,x∈Ω. ( 5)  Where0 <α…  相似文献   

10.
一、选择题(10×5分=50分)1.若集合A={z| |x|≤1},B={x|x≥O},则 A∩B=A.{x|-1≤x≤1}B.|x|x≥01C.{z|0≤x≤1}D.(Φ)2.复数3+2i/2-3i=A.I B.-I C.12-13i D.12+13i3.在△ABC,已知cosA=5/13,sinB=3/5,则cosC的值为A.16/65 B.56/65 C.16/65或56/65 D.-16/65或56/65  相似文献   

11.
The interior proximal extragradient method for solving equilibrium problems   总被引:1,自引:0,他引:1  
In this article we present a new and efficient method for solving equilibrium problems on polyhedra. The method is based on an interior-quadratic proximal term which replaces the usual quadratic proximal term. This leads to an interior proximal type algorithm. Each iteration consists in a prediction step followed by a correction step as in the extragradient method. In a first algorithm each of these steps is obtained by solving an unconstrained minimization problem, while in a second algorithm the correction step is replaced by an Armijo-backtracking linesearch followed by an hyperplane projection step. We prove that our algorithms are convergent under mild assumptions: pseudomonotonicity for the two algorithms and a Lipschitz property for the first one. Finally we present some numerical experiments to illustrate the behavior of the proposed algorithms.  相似文献   

12.
We propose a new algorithm for the total variation based on image denoising problem. The split Bregman method is used to convert an unconstrained minimization denoising problem to a linear system in the outer iteration. An algebraic multi-grid method is applied to solve the linear system in the inner iteration. Furthermore, Krylov subspace acceleration is adopted to improve convergence in the outer iteration. Numerical experiments demonstrate that this algorithm is efficient even for images with large signal-to-noise ratio.  相似文献   

13.
In this paper, we consider the box constrained nonlinear integer programming problem. We present an auxiliary function, which has the same discrete global minimizers as the problem. The minimization of the function using a discrete local search method can escape successfully from previously converged discrete local minimizers by taking increasing values of a parameter. We propose an algorithm to find a global minimizer of the box constrained nonlinear integer programming problem. The algorithm minimizes the auxiliary function from random initial points. We prove that the algorithm can converge asymptotically with probability one. Numerical experiments on a set of test problems show that the algorithm is efficient and robust.  相似文献   

14.
许伟志  殷弘  蒋凌云 《数学杂志》2015,35(4):881-888
本文研究了SENSE模型下从部分傅里叶数据中信号的重建问题.利用类Dykstra近点方法和Bregman迭代方法,我们获得了一种SENSE模型下信号重建的加速类-Dykstra近点有效算法,并证明了该算法的收敛性.实验仿真显示,该方法比经典的分裂Bregman方法有效.  相似文献   

15.
本文给出了一个计算Adomian多项式的新算法,并将其用于求微分方程的近似 解.我们的算法比原有算法效率高,且易于在计算机上实现.我们在Maple中实现了这一 算法,并通过30多个微分方程的求解验证了新算法的有效性.  相似文献   

16.
在这篇论文里,有机地把外逼近方法与分枝定界技术结合起来,提出了解带有二次约束非凸二次规划问题的一个分枝缩减方法;给出了原问题的一个新的线性规划松弛,以便确定它在超矩形上全局最优值的一个下界;利用超矩形的一个深度二级剖分方法,以及超矩形的缩减和删除技术,提高算法的收敛速度;证明了在知道原问题可行点的条件下,该算法在有限步里就可以获得原问题的一个全局最优化解,并且用一个例子说明了该算法是有效的.  相似文献   

17.
We propose an SQP-type algorithm for solving nonlinear second-order cone programming (NSOCP) problems. At every iteration, the algorithm solves a convex SOCP subproblem in which the constraints involve linear approximations of the constraint functions in the original problem and the objective function is a convex quadratic function. Those subproblems can be transformed into linear SOCP problems, for which efficient interior point solvers are available. We establish global convergence and local quadratic convergence of the algorithm under appropriate assumptions. We report numerical results to examine the effectiveness of the algorithm. This work was supported in part by the Scientific Research Grant-in-Aid from Japan Society for the Promotion of Science.  相似文献   

18.
In this paper, we propose new technique for solving stiff system of ordinary differential equations. This algorithm is based on Laplace transform and homotopy perturbation methods. The new technique is applied to solving two mathematical models of stiff problem. We show that the present approach is relatively easy, efficient and highly accurate.  相似文献   

19.
本文提出了离散均值-方差投资组合模型的一种新的精确算法.该算法是一个基于拉格朗日松弛和Bundle对偶搜索的分枝定界算法.我们分别用随机产生的数据和美国股票市场的真实数据进行了数值实验,并与传统次梯度对偶搜索进行了比较,数值结果表明本文提出的算法对解决中小规模的离散投资组合问题是有效的.  相似文献   

20.
A new Alternating-Direction Sinc–Galerkin (ADSG) method is developed and contrasted with classical Sinc–Galerkin methods. It is derived from an iterative scheme for solving the Lyapunov equation that arises when a symmetric Sinc–Galerkin method is used to approximate the solution of elliptic partial differential equations. We include parameter choices (derived from numerical experiments) that simplify existing alternating-direction algorithms. We compare the new scheme to a standard method employing Gaussian elimination on a system produced using the Kronecker product and Kronecker sum, as well as to a more efficient algorithm employing matrix diagonalization. We note that the ADSG method easily outperforms Gaussian elimination on the Kronecker sum and, while competitive with matrix diagonalization, does not require the computation of eigenvalues and eigenvectors.  相似文献   

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