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1.
关于《矩阵正定性的进一步推广》一文的注记 总被引:4,自引:0,他引:4
关于《矩阵正定性的进一步推广》一文的注记黎奇升(湖南吉首大学数学系,吉首416000)文[1]给出了下面定义并讨论了它们的一些性质.定义 设A∈R ̄(n×n),若对任何0≠X∈R ̄(n×1),都有正定矩阵S=Sx,使X ̄TSxAX>0,则称A为广义正... 相似文献
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设D,D1 和D2 是实有限可除代数,Mmn(D)是D上所有m ×n矩阵的R线性空间. 若两个R线性算子f:Mm n(D1)→Mmn(D2) 和g:Mnm (D1) →Mnm (D2)满足f(A)+ = g(A+ )对于一切的A∈Mm n(D1)均成立,则称(f, g) 是一个保矩阵MP逆的共变算子对. 当m in(m , n)2时,本文刻划了所有这种共变算子对(f, g) 的结构. 相似文献
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交换主理想整环上立方幂等矩阵的线性保持 总被引:1,自引:0,他引:1
设R(≠F_3)是特征不为2的交换主理想整环,M_n(R)定义R上的n×n矩阵模,本文刻划当n≥m时从M_n(R)到M_n(R)的保持立方幂等矩阵的线性映射的形式,由此推广了Chan和Lim的一个结果([1,定理3]). 相似文献
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设A是Banach空间X上的自反算子代数,并且A的不变子空间格LatA满足 0+≠0和X_≠X,a:A→A是环自同构.如果X是实空间,并且dim X >1;则存在X上的线性有界可逆算子A,使得a(T)=ATA~(-1);T∈A:如果X是复空间,并且dim X =∞,则a(T)=ATA~(-1),T∈A.其中A:X→X是线性、或者共轭线性有界可逆算子. 相似文献
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1.引 言 设A∈Cm×n,M和N分别为m和n阶Hermite正定阵,考虑下列方程 (1) AXA=A (2) XAX=X (3)(AX)*=AX (4)(XA)*=XA (3M)(MAX)*=MAX (4N)(NXA)*=NXA 如果X∈Cn×m满足条件(1)和(2),则称X为A的自反广义逆,记作X=A(1,2);如果 X满足条件(2),则称X为 A的{2}逆,记作 X=A(2);如果X满足(1)-(4),则称X为 A的 M-P逆,记作X=A+;如果X满足(1)、(2)、(3M)、(4N),则称 X为 A的加权… 相似文献
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本文给出了有限交换局部环R上无限线性群GL(R)=∪nGLnR的Sylowp-子群的形式.令M是有限交换局部环R的唯一极大理想,k=R/M为R的剩余类域.用X(k)表示k的特征,并假定P与x(k)互素.作者证明了:GL(R)的任一Sylowp-子群S或者同构于的可数无限直积与P(j)的无限直积的直积(当P≠2或P=2,X(k)β≡1(mod4))或者同构于Pi的无限直积与P(j)的无限直积的直积(当P=2,X(k)β≡3(mod4)),这里,只是GL(epi)R(分别地,GL(2ri)R)的Sylowp-子群,P(j))同构于P=∪i∈Ipi,I是可数集. 相似文献
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Hadamard积和酉不变范数不等式 总被引:9,自引:0,他引:9
设Mn,m是n×m复矩阵空间,Mn≡Mn,n.对于Hermite阵G,H∈Mn,GH表示G-H半正定.记A和B的Hadamard积为AB.本文证明了若A,B∈Mn正定,而X,Y∈Mn,m任意,则(XA-1X)(YB-1Y)(XY)(AB)-1(XY),XA-1X+YB-1Y(X+Y)(A+B)-1(X+Y).这推广和统一了一些现存的结果.设‖·‖为任意酉不变范数,I是单位矩阵.本文还证明了对于X∈Mn,m和A∈Mn,B∈Mm,若AI,BI,则函数f(p)=‖ApX+XBp‖在[0,∞)上单调递增. 相似文献
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本文结果是:设A是φ-满射环R上的非拟纯量可逆n×n矩阵,βj,γj(尔≤j≤n)是R中任意元素,它们满足Πnj=1βjγj=detA,则存在n阶阵B和C满足PAP-1=BC,其中B是下三角阵,C是上三角阵,P∈GLn(R).进一步,可以取B使βj(1≤j≤n)位于B的主对角线上,同时可以取C使γj(1≤j≤n)位于C的主对角线上. 相似文献
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This paper deals with the stability of the intersection of a given set
with the solution,
, of a given linear system whose coefficients can be arbitrarily perturbed. In the optimization context, the fixed constraint
set X can be the solution set of the (possibly nonlinear) system formed by all the exact constraints (e.g., the sign constraints),
a discrete subset of
(as
or { 0,1}
n
, as it happens in integer or Boolean programming) as well as the intersection of both kind of sets. Conditions are given
for the intersection
to remain nonempty (or empty) under sufficiently small perturbations of the data.
Research supported by Fondecyt Grant 1020(7020)-646.
Research supported by DGES and FEDER, Grant BFM2002-04114-C02-01 相似文献
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The linear discrepancy of a poset P is the least k such that there is a linear extension L of P such that if x and y are incomparable in P, then |h
L
(x)–h
L
(y)|≤k, where h
L
(x) is the height of x in L. Tanenbaum, Trenk, and Fishburn characterized the posets of linear discrepancy 1 as the semiorders of width 2 and posed the
problem of characterizing the posets of linear discrepancy 2. We show that this problem is equivalent to finding the posets
with linear discrepancy equal to 3 having the property that the deletion of any point results in a reduction in the linear
discrepancy. Howard determined that there are infinitely many such posets of width 2. We complete the forbidden subposet characterization
of posets with linear discrepancy equal to 2 by finding the minimal posets of width 3 with linear discrepancy equal to 3.
We do so by showing that, with a small number of exceptions, they can all be derived from the list for width 2 by the removal
of specific comparisons.
The first and second authors were supported during this research by National Science Foundation VIGRE grant DMS-0135290. 相似文献
14.
Jong-Shi Pang 《Mathematical Programming》1977,13(1):360-363
LetK be the class ofn × n matricesM such that for everyn-vectorq for which the linear complementarity problem (q, M) is feasible, then the problem (q, M) has a solution. Recently, a characterization ofK has been obtained by Mangasarian [5] in his study of solving linear complementarity problems as linear programs. This note proves a result which improves on such a characterization.Research sponsored by the United States Army under Contract No. DAAG29-75-C-0024 and the National Science Foundation under Grant No. MCS75-17385. 相似文献
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We give an explicit representation of the class of linear permutation polynomials. By the representation, the number of them can be computed easily. 相似文献
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Let , and be linear spaces and let A and B be linear relations from to and from to , respectively. The main result of this note is a formula which relates the nullities and the defects of the relations A and B with those of the product relation BA. 相似文献
17.
Graham Brightwell 《Discrete Mathematics》2010,310(5):1016-1025
We consider a natural analogue of the graph linear arrangement problem for posets. Let P=(X,?) be a poset that is not an antichain, and let λ:X→[n] be an order-preserving bijection, that is, a linear extension of P. For any relation a?b of P, the distance between a and b in λ is λ(b)−λ(a). The average relational distance of λ, denoted , is the average of these distances over all relations in P. We show that we can find a linear extension of P that maximises in polynomial time. Furthermore, we show that this maximum is at least , and this bound is extremal. 相似文献
18.
Roger B. Myerson 《Mathematical Programming》1981,21(1):182-189
An algorithm is presented for computing equilibria in a linear monetary economy, that is, an exchange economy in which all individuals have linear utility functions and in which goods are bought and sold only in exchange for money. The algorithm computes the equilibrium prices by solving a finite sequence of linear programming problems. 相似文献
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A new method for a class of linear variational inequalities 总被引:14,自引:0,他引:14
In this paper we introduce a new iterative scheme for the numerical solution of a class of linear variational inequalities. Each iteration of the method consists essentially only of a projection to a closed convex set and two matrix-vector multiplications. Both the method and the convergence proof are very simple.This work is supported by the National Natural Science Foundation of the P.R. China and NSF of Jiangsu. 相似文献