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1.
广义严格对角占优矩阵的判定   总被引:10,自引:0,他引:10  
1引言设A=(aij)Cnxn,若对每一iN={1,2,…,n}都有则称A为对角占优矩阵,记为ADυ;若(1)式中每一不等号都是严格的,则称A为严格对角占优矩阵,记为AD.若存在正对角阵X使AXDυ(或AXD),则称A为广义(或广义严格)对角占优矩阵;记为ADΥ(或AD).广义严格对角占优矩阵的判定在计算数学和矩阵论的研究中占有重要的地位,文[1]和[2]分别定义了α-对角占优矩阵和双对角占优矩阵,讨论了广义严格对角占优矩阵的判定及性质,本文引进了α双对角占优矩阵的概念,得到了广义严格对角占优矩…  相似文献   

2.
1引言 设A=(a_η)∈Cm~(3n),若存在正对角阵D.使得AD为严格对角占优矩阵,则A称为广义严格对角占优矩阵,记作A∈SGDDM.  相似文献   

3.
严格对角占优矩阵行列式模下界的估计和应用   总被引:2,自引:0,他引:2  
严格对角占优矩阵行列式模下界的估计和应用胡永建(北京师范大学数学系90级100875)对于严格对角占优矩阵A=(aij)∈Mn(C),即有它的行列式摸有一个下界:在本文,我们用归纳法来证明比它更好的下界估计(定理1),并讨论其应用.有关结果见文献[1...  相似文献   

4.
局部双对角占优矩阵及应用   总被引:9,自引:0,他引:9  
逄明贤 《数学学报》1995,38(4):442-450
本文引进了局部双对角占优矩阵的概念,讨论了这类矩阵的性质,给出了局部双对角占优矩阵是广义严格对角占优矩阵的等价表征,得到了M-矩阵的新表征,推广了[1-12]的相应结果。  相似文献   

5.
非奇H矩阵与M-矩阵的等价条件   总被引:3,自引:0,他引:3  
本文引进了局部对角占优矩阵的概念,得到了非奇H矩阵与M-矩阵的等价条件与判定准则,改进了文[1]的主要结果.  相似文献   

6.
设A为实方阵,熟知,若A+AT正定,则称A亚正定;若存在正对角阵D,使得DA+(DA)T正定,则称人广义亚正定,又若使得 DA+(DA)T为正定矩阵,则称 D为A的 Valterra乘子.易证下列结果. 定理 1设 A=(aij) ∈ Rnxn,且 A= 则 A亚正定的充要条件是亚正定. 2理 2设A=(aij)nxn,则 A存在Volterra乘子的充要条件是A为广义亚正定阵. 定理 3设 A=(aij)nxn,A分块如定理 2,若 A11,A22亚正定,则 A存在 Volterra乘子. 定理 4设 A=(aij)…  相似文献   

7.
非奇异H矩阵的充分条件   总被引:23,自引:1,他引:22  
1 引言 设A=(a_(ij))∈C~(n,n),R_i(A)=sum from j≠i to(|a_(ij)|,i,j∈N={1,2,…,n}。若|a_(ij)|≥R_i(A),i∈N,则称A为对角占优矩阵,记为A∈D_0;若不等式中每个不等号都是严格的,则称A为严格对角占优矩阵,记为A∈D。若存在正对角矩阵X,使得AX∈D,则称A为广义严格对角占优矩阵,记为A∈D。  相似文献   

8.
按环路α-连对角占优阵及应用   总被引:4,自引:0,他引:4  
李竹香  逄明贤 《计算数学》2001,23(3):271-278
1.引言与记号 利用矩阵的对角占优性研究矩阵的特征值分布和非奇H矩阵的判定,是数值代数的重要课题.[1]-[4]给出了利用 Ostrowski定理及连对角占优性判定非奇 H-矩阵的最新成果.本文引入按环路α-连对角占优概念,给出了非奇H-矩阵的判定条件及等价表征,简化了计算,改进与推广了[1]-[9]的相应结果. 设A=.Γ(A)表 A的方向图,其顶点集及弧集分别记作 V(A)及 E(A),eij表从顶点i到顶点 j的弧, C(A)表 Γ(A)中非平凡环路集合.对任意固定 α E[0,1]还记*k伪行、列足…  相似文献   

9.
1、引言 各类对角占优矩阵是数值代数和矩阵分析研究中的重要课题之一.对于线性方程组AX=6,当系数矩阵A为(块)对角占优矩阵或广义(块)对角占优矩阵时,许多经典的迭代算法均是收敛的,同时对目前提出的一些修正算法也是收敛的.因此,判断一个矩阵是否是广义(块)对角占优矩阵具有重要意义.国内外许多学者都做了不少研究(见文[1.5]),本文给出了几个广义对角占优矩阵的判别方法.  相似文献   

10.
矩阵对角占优性的推广及应用   总被引:38,自引:1,他引:37  
§1.引言设 A=(a_(ij))_(n×n)为一复矩阵,若有一正向量 d=(d_1,d_2,…,d_n)~T 使得d_i|a_(ij)|≥sum from j≠1 d_j|a_(ij)|,(1)对每一 i∈N={1,2,…,n}都成立,则称 A 为广义对角占优矩阵,记为 A∈D_0~*;如若(1)式中每一不等号都是严格的,则称 A 为广义严格对角占优矩阵,记为 A∈D~*.特别地,当 d=(1,1,…,1)~T 时,A∈D_0~*及 A∈D~*即是通常的对角占优与严格对角占优,分别记作 A∈D_0及 A∈D.利用矩阵的对角占优性质讨论其特征值分布是矩阵论中的重要课题,文献[5]—[10]给出了这方面的重要结果.n 阶实方阵 A 称为 M-矩阵,如果 A具有形式:A=sI-B,s>ρ(B),其中 B 为 n 阶非负方阵,ρ(B)表 B 之谱半径,利用广义严格对角占优的概念,文[1]给出了 M-矩阵的等价表征:若 n 阶实方阵  相似文献   

11.
詹小平  蔡海涛 《数学学报》2003,46(2):237-244
文[4]对简单形式的微分多项式fkf’+a的零点分布进行了讨论,文[1]对一般形式的微分多项式fkQ[f]+P[f]的零点分布进行了讨论.但由于极点给证明带来的困难,这些工作主要是对整函数来做的.本文证明了任一满足δ(∞,f)>k+2ΓQ+3ΓP+2/2k+2ΓQ+1的超越亚纯函数f,微分多项式fkQ[f]+P[f]在不含f,Q[f]极点和P[f]零、极点的可数个圆盘并集之外有无穷多个零点,其中k≥3Γp+2,而ΓQ,ΓP分别是f的微分多项式Q[f],P[f]的权.文[1]和[2,4,6]中的结论是本文结论的特殊情况.  相似文献   

12.
A. Serhir 《代数通讯》2013,41(8):2531-2538
Let D [d] =(a,b/F) a quaternion divisior algebra over a field F of characteristic ? 2. Denote 1, i, j , k the basis of D, such that i2[d] n, j2[d] b, ij [d] -ji [d] k and A :D → D the involution given by i [d] -i, j [d] j (and k [d] k). In [LE] D. LEWIS asks the following question :Does there exist a quadratic Pfister form [S p. 721 [d] such that the hermitian form [d] [d] D is isotropic over (D, [d]) but not hyperbolic &; In this note, we show that the answer of this question is negative, so that the hermitien level [§I], when it is finite, of (D, A) is a power of two. This result holds for quaternion algebras with standard involution [LE].  相似文献   

13.
既是[a,b]-覆盖又是[a,b]-消去的图称为[a,b]-对等图.本文研究了最小度和[a,b]-对等图之间的关系,给出了一个图是[a,b]-对等图的关于最小度的充分条件.  相似文献   

14.
Weak affine spaces have been introduced in [6] and [7] by E. SPERNER. They can be algebraically described by quasimodules. in [8] E. SPERNER constructed quasimodules by nearfields. In [9] and [10] he used more general algebraic structures for this construction and in [5] the author described a generalisation of this method. In this note we give a geometric and algebraic characterization of those weak affine spaces which can be constructed in this way.  相似文献   

15.
DefinitionlLl]I,etXbeaHausdorffTopologicalspacewhichhaspartiallyorderedstructure.WesayXisasemiorderedTopologicalSpace,ifforanytwonets{x.Ir6T}and{YrlrET}inX,x,相似文献   

16.
17.
It is unknown (cf. Hill and Newton [8] or Hamada [3]) whether or not there exists a ternary [50,5,32] code meeting the Griesmer bound. The purpose of this paper is to prove the nonexistence of ternary [50,5,32] codes. Since there exists a ternary [51,5,32] code, this implies that n3(5,32) = 51, where n3(k,d) denotes the smallest value of n for which there exists a ternary [n,k,d] code.  相似文献   

18.
There already exists a fairly complete theory for the problems of estimation and stochastic optimal control for linear distributed parameter systems, with Gaussian or non Gaussian noise disturbance. In [8] and [12] generalizations of the familiar finite dimensional results of the Kalman-Bucy filter and the separation principle are obtained using an abstract input-output Hilbert space representation for the system. However, in [8] and [12] all the input operators are assumed to be bounded and so it does not cover the important practical cases of control and noise on submanifolds of the spatial domain or point observations. Here we introduce unbounded system operators in the abstract input-output Hilbert space representation and thus extend all the results of [8] and [12] to allow for point observations and noise and control on submanifolds including the boundary. The theory is illustrated by several examples.  相似文献   

19.
There already exist a fairly complete theroy for the problem of estimation and stochastic optimal control for linear distribution parameter systems, with Gaussian or non-Gaussian noise disturbance. In [8] and [12] generalizations of the familiar finite dimensional results of the kalman-bucy filter and the separtion principle are obtained using an abstract input-output Hilbert space representation for the system. However , in [8] and [12] all the input-operators are assumed to be bounded and so it does not cover the important pratical cases of control and noise on submanifolds of the spatial domain or point observations. Here we introduce unbounded system operators in the abstract iput-output Hilbert space reperesentation and thus extend all the results if [8] and [12] to allow for point observations and noise and control on submanifolds including the boundary. the theroy is illustrated by several examples  相似文献   

20.
We use elementary methods to prove a sufficient and necessary condition for a Sobolev interpolation inequalities with weight [ILLM0001] where [ILLM0001] are real numbers, and [ILLM0001]  相似文献   

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