偶阶等差数列幻方新填法

１ 双偶阶等差数列幻方新填法与证明 定义 设ｎ为不小于３的整数,由公差不为０的等差数列前ｎ２项构成的ｎ阶方阵,若每行、每列、主对角线、副对角线上诸元素之和为常数Ｓｎ,则称此方阵为ｎ阶等差数列幻方,Ｓｎ称为幻方值． 若ｎ＝４ｋ（ｋ ∈ Ｎ）,称其为双偶阶幻方;ｎ＝４ｋ＋２（ｋ ∈ Ｎ）,称其为单偶阶幻方． 为了便于问题研究,我们给出１,２,…,ｎ２这个等差数列幻方的新填法,其它等差数列完全可以同样地进行． 首先,把一个４ｋ × ４ｋ方阵如表１所示分划．其中Ａ、Ｃ、ＩＧ、Ｅ为正方形块,称为不变部分．Ｂ、Ｈ　、Ｄ…     

恰有t行含s圈正元的布尔方阵的幂敛指数

设Ｄｎ，ｓ（ｔ）是恰有ｔ行含ｓ圈正元的ｎ阶布尔方阵的集合，ｓｔｎ．本文给出了当ｓ＝１或ｓ为素数时Ｄｎ，ｓ（ｔ）中矩阵的幂敛指数的一个上界，证明了除ｔ＞ｎ－ｓ（ｎ－１）＋１／４－３／２，且ｓ与ｎ不互素外，这个上界可以达到，对Ｄｎ，ｓ（ｔ）中幂敛指数达到这个上界的矩阵作了部分刻划．     

二阶方阵的平方根和三角方阵的三角平方根

二阶方阵的平方根和三角方阵的三角平方根胡结梅（南昌航空工业学院基础一部３３００３４）定义设Ａ是一个ｎ阶方阵，若存在ｎ阶方阵Ｂ，使Ｂ２＝Ａ，则称方阵Ｂ是方阵Ａ的一个平方根．以ｄｅｔＡ表示方阵Ａ的行列式，则由定义得：ｄｅｔＢ＝±ｄｅｔＡ．下面的定理１给出...     

Drazin逆的一个性质特征

对任意的ｎ阶方阵A ∈C^n×n，本文给出它的Ｄｒａｚｉｎ逆的一个重要性质（见定理１），并给出Ａ的Ｄ－逆的一个求解算法，从而推广了［２］中的结论．     

复射影空间的等参子流形

本文给出了复射影空间Ｐ＿ｎ（Ｃ）上的等参映射定义，并证明了等参映射ｆ在Ｈｏｐｆ主丛π：Ｓ￣（２ｎ＋１）→Ｐ＿ｎ（Ｃ）下的水平提升为Ｓ￣（２ｎ＋１）的等参映射。同时，利用对称空间的表示给出了Ｐ＿ｎ（Ｃ）上等参子流形的例子．     

带有中止检查规则（n－i）的CSP－1方案

本文引人转移概率母函数及幂级数等方法讨论带有中止规则（ｎ＊－ｉ）的连续抽样方案ＣＳＰ－１的中止概率Ｐ＊得到了Ｐ＊作为ＣＳＰ－１方案的度量的理论特性，证明了Ｄｏｄｇｅ型ＣＳＰ－１方案与带有中止规则（ｎ＊－ｉ）的ＣＳＰ－１方案具有相同的ＡＯＱ，ＡＦＩ，ＯＣ函数．文末还给出了一些数值结果．     

少圈二重覆盖平面近三角剖分图的生成元

令Ｇ为一具有ｎ个节点的平面近三角剖分图,Ｃ为Ｇ的一个少圈二重覆盖（ＳＣＤＣ）．本文首先给出了Ｇ的一些生成元,由此可以得到Ｇ的一个ＳＣＤＣ．若Ｇ为一外平面近三角剖分图,得到 ｜Ｃ｜≤ｎ－２的一充分必要条件;若 Ｇ至少有一个内点,得到｜Ｃ｜≤ｎ－２的一充分条件．     

实有限可除代数间保矩阵M—P逆的共变算子对

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ＭＰ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．     

一四元数矩阵方程组的实部半正定解

设Ａ是一个ｎ阶实四元数方阵，若对任意的非零ｎ元列向量ｘ，有ｘＡｘ的实部非负，则称Ａ是一个实部半正定阵，本文给出了实四元数矩阵方程组。     

恰有t行含对称正元的布尔方阵的幂敛指数的估值

设Ｄｎ，２（ｔ）为恰有ｔ行含对称正元的ｎ阶布尔方阵的集合，２≤ｔ≤ｎ。本文证明了，对于任给Ａ∈Ｄｎ，２（ｔ），幂敛指数ｋ（Ａ）≤∫（ｎ－ｔ－１）＾２＋１，３ｎ－ｔ－２，当ｔ≤ｎ－［３＋√８ｎ－７／２］当ｔ〉ｎ－［３＋√８ｎ－７／２］，这里［ｘ］表示不小于ｘ的最小整数。同时，我们还证明了这个界是可以达到的，并且对Ｄｎ，２（ｔ）的极矩阵集合作了部分刻划。     

Decomposable symmetric designs

The first infinite families of symmetric designs were obtained from finite projective geometries, Hadamard matrices, and difference sets. In this paper we describe two general methods of constructing symmetric designs that give rise to the parameters of all other known infinite families of symmetric designs. The method of global decomposition produces an incidence matrix of a symmetric design as a block matrix with each block being a zero matrix or an incidence matrix of a smaller symmetric design. The method of local decomposition represents incidence matrices of a residual and a derived design of a symmetric design as block matrices with each block being a zero matrix or an incidence matrix of a smaller residual or derived design, respectively.     

判定3,4或5阶对称矩阵偕正性的算法

文献[1]给出了判定阶数不大于5的对称矩阵偕正性的充分必要条件.本文在此基础上,进一步给出了它们严格偕正的条件,并提出了三个算法,它们能够用来有效地判定3,4,5阶对称矩阵严格偕正、偕正或非偕正.     

A Characterization of a Class of Symmetric(0,1)Matrices

ＡＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｏｆａＣｌａｓｓｏｆＳｙｍｍｅｔｒｉｃ（０，１）ＭａｔｒｉｃｅｓＬｉＷｅｎ（黎稳）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＳｏｕｔｈＣｈｉｎａＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｇｕａｎｚｈｏｎ，５１０６３１...     

Highly symmetric generalized circulant permutation matrices

In this paper we investigate generalized circulant permutation matrices of composite order. We give a complete characterization of the order and the structure of symmetric generalized k-circulant permutation matrices in terms of circulant and retrocirculant block (0, 1)-matrices in which each block contains exactly one or two entries 1. In particular, we prove that a generalized k-circulant matrix A of composite order n = km is symmetric if and only if either k = m − 1 or k ≡ 0 or k ≡ 1 mod m, and we obtain three basic symmetric generalized k-circulant permutation matrices, from which all others are obtained via permutations of the blocks or by direct sums. Furthermore, we extend the characterization of these matrices to centrosymmetric matrices.     

General Moments of the Inverse Real Wishart Distribution and Orthogonal Weingarten Functions

We study a random positive definite symmetric matrix distributed according to a real Wishart distribution. We compute general moments of the random matrix and of its inverse explicitly. To do so, we employ the orthogonal Weingarten function, which was recently introduced in the study of Haar-distributed orthogonal matrices. As applications, we give formulas for moments of traces of a Wishart matrix and its inverse.     

无界分块算子矩阵的谱分布

本文首先给出次对角元有界的2×2阶无界算子矩阵的Gershgorin定理,然后利用主对角元算子的谱和数值域刻画整个算子矩阵的谱分布.特别地,当次对角元算子互为共轭(反共轭)算子时,结合二次数值域和Gershgorin定理对谱分布给出更精细的描述.     

STABLE DOUBLE LR ALGORITHM AND ITS ERROR ANALYSIS

In this paper, the normative matrices and their double LR transformation with origin shifts are defined, and the essential relationship between the double LR transformation of a normative matrix and the QR transformation of the related symmetric tridiagonal matrix is proved. We obtain a stable double LR algorithm for double LR transformation of normative matrices and give the error analysis of our algorithm. The operation number of the stable double LR algorithm for normative matrices is only four sevenths of the rational QR algorithm for reed symmetric tridiagonal matrices.     

Extremal inverse eigenvalue problem for symmetric doubly arrow matrices

In this paper, we consider the following inverse eigenvalue problem: to construct a real symmetric doubly arrow matrix A from the minimal and maximal eigenvalues of all its leading principal submatrices. The necessary and sufficient condition for the solvability of the problem is derived. We also give a necessary and sufficient condition in order that the constructed matrices can be nonnegative. Our results are constructive and they generate algorithmic procedures to construct such matrices.     

有限局部环上对称矩阵的计数定理(Ⅰ)

设A_n(R)是有限局部环Z/p~k Z上n阶对称矩阵的集合,这里n≥2．p是大于2素数,p≡1(mod4)且k＞1．通过确定有限局部环Z/p~k Z上对称矩阵的标准型,计算出A_n(R)在线性群GL_n(R)作用下的轨道数,从而计算出由特定对称矩阵确定的正交群的阶以及与特定对称矩阵在同一轨道的对称矩阵的阶．