Symplectic Shifted Tableaux and Deformations of Weyl's Denominator Formula for sp(2n)

A determinantal expansion due to Okada is used to derive both a deformation of Weyl's denominator formula for the Lie algebra sp(2n) of the symplectic group and a further generalisation involving a product of the deformed denominator with a deformation of flagged characters of sp(2n). In each case the relevant expansion is expressed in terms of certain shifted sp(2n)-standard tableaux. It is then re-expressed, first in terms of monotone patterns and then in terms of alternating sign matrices.     

A Generalization of Alternating Sign Matrices

In alternating sign matrices, the first and last nonzero entry in each row and column is specified to be +1. Such matrices always exist. We investigate a generalization by specifying independently the sign of the first and last nonzero entry in each row and column to be either a +1 or a ?1. We determine necessary and sufficient conditions for such matrices to exist whose proof contains an algorithm for their construction.     

U-Turn Alternating Sign Matrices,Symplectic Shifted Tableaux and their Weighted Enumeration

Alternating sign matrices with a U-turn boundary (UASMs) are a recent generalization of ordinary alternating sign matrices. Here we show that variations of these matrices are in bijective correspondence with certain symplectic shifted tableaux that were recently introduced in the context of a symplectic version of Tokuyama’s deformation of Weyl’s denominator formula. This bijection yields a formula for the weighted enumeration of UASMs. In this connection use is made of the link between UASMs and certain square ice configuration matrices.     

k次幂非正的符号模式矩阵

本首先对使得A^K≤0的符号模式矩阵A进行了刻画（k为任意正整数），进而决定了这类矩阵中负元个数的最大值。最后给出了使得A^2≤0的符号模式矩阵A的充分必要条件。     

广义Lucas数的倒数和及交错和若干公式的拓广

The purpose of this article is to provide the inversion relationships between the reciprocal sum S(1,2,…,m) and the alternating sum T(1,2,…,m) for generalized Lucas numbers which generalizes the Melham's results.     

Alternating-Sign Matrices and Domino Tilings (Part II)

We continue the study of the family of planar regions dubbed Aztec diamonds in our earlier article and study the ways in which these regions can be tiled by dominoes. Two more proofs of the main formula are given. The first uses the representation theory of GL(n). The second is more combinatorial and produces a generating function that gives not only the number of domino tilings of the Aztec diamond of order n but also information about the orientation of the dominoes (vertical versus horizontal) and the accessibility of one tiling from another by means of local modifications. Lastly, we explore a connection between the combinatorial objects studied in this paper and the square-ice model studied by Lieb.     

Alternating-Sign Matrices and Domino Tilings (Part I)

We introduce a family of planar regions, called Aztec diamonds, and study tilings of these regions by dominoes. Our main result is that the Aztec diamond of order n has exactly 2 ^n(n+1)/2 domino tilings. In this, the first half of a two-part paper, we give two proofs of this formula. The first proof exploits a connection between domino tilings and the alternating-sign matrices of Mills, Robbins, and Rumsey. In particular, a domino tiling of an Aztec diamond corresponds to a compatible pair of alternating-sign matrices. The second proof of our formula uses monotone triangles, which constitute another form taken by alternating-sign matrices; by assigning each monotone triangle a suitable weight, we can count domino tilings of an Aztec diamond.     

The operator formula for monotone triangles - simplified proof and three generalizations

We provide a simplified proof of our operator formula for the number of monotone triangles with prescribed bottom row, which enables us to deduce three generalizations of the formula. One of the generalizations concerns a certain weighted enumeration of monotone triangles which specializes to the weighted enumeration of alternating sign matrices with respect to the number of −1s in the matrix when prescribing (1,2,…,n) as the bottom row of the monotone triangle.     

三角形Toeplize矩阵的三角本原指数

讨论了三角形 Toeplize矩阵与一元多项式的关系以及非负三角形 Toeplize矩阵的三角本原指数 ,证明了 n阶非负上三角 Toeplize矩阵的三角本原指数集 Sn={1 ,2 ,… ,k-1 ,k,k1,k2 ,… ,ks,n-1 },其中 k是满足 k >4n -3 -12 和 n -1k +1 =n -1k 的最小整数 .     

Pascal三角形与Pascal矩阵

Pascal三角形中隐含着二项系数的许多相关性质 .本文从线性代数的观点研究了 Pascal矩阵的性质及其应用 ,并将这种矩阵推广到了更一般的形式     

Some Cubic Summation and Transformation Formulas

q-Analogues of two cubic summation formulas that have recently caught the attention of Bill Gosper are found by first showing their connection with the q-binomial formula and then using some known transformation formulas. We also find a q-extension of a cubic transformation formula involving Gauss' hypergeometric function, which turns out to be a relation between balanced and very-well-poised 109 series.     

中心对称与中心交错矩阵几何

应用对称(交错)矩阵几何基本定理,本文证明了域上中心对称(交错)矩阵几何基本定理.     

Sign patterns for eigenmatrices of nonnegative matrices

For a square (0,?1,??1) sign pattern matrix S, denote the qualitative class of S by Q(S). In this article, we investigate the relationship between sign patterns and matrices that diagonalize an irreducible nonnegative matrix. We explicitly describe the sign patterns S such that every matrix in Q(S) diagonalizes some irreducible nonnegative matrix. Further, we characterize the sign patterns S such that some member of Q(S) diagonalizes an irreducible nonnegative matrix. Finally, we provide necessary and sufficient conditions for a multiset of real numbers to be realized as the spectrum of an irreducible nonnegative matrix M that is diagonalized by a matrix in the qualitative class of some S ² NS sign pattern.     

逆H矩阵的新性质

本文在文[4]给出的逆H矩阵定义的基础上，给出了逆H矩阵的新性质．     

行分块矩阵值域上正交投影的展开式

We give in this note some expansion formulas for the orthogonal projectors onto the range of the row block matrix [ A, B ], and use the expansion formulas to examine relations among the orthogonal projectors onto the ranges of A, B and [A, B]. In particular, we present some identifying conditions for a pair of orthogonal projectors of the same size to commute.     

秩为1矩阵的性质及应用

给出了秩1矩阵的结构,讨论了这类矩阵在矩阵运算、对角化、标准型等方面的性质,推广和改进了文[1]的一些相关结果,并指出了它的若干应用,重点讨论了一类矩阵,得到了有关结论和方法.     

带变号系数的经典Gelfand模型的正解

考察了经典Gelfand模型的正解的存在与迭代,其中非线性项的系数允许在[0,1]中改变符号。利用单调迭代方法得到了一个正解存在定理,给出了相应的迭代程序和收敛速度。由于这个迭代程序是从零函数开始的,因此它是简单、可行并且有效的。     

非负矩阵的一些算法

本文利用有限图论和齐次有限马尔可夫链理论的有关命题和算法得到了不同于[1]、[3]的算法:(1)有限阶非负矩阵可约性的判别、有限阶可约矩阵化为主对角线上都为不可约子块的分块三角阵的算法;(2)有限阶不可约矩阵的Frobenius表示的算法.对上述二算法本文还分别给出了直观简便的图示法.     

复方阵的一种分解及应用

本文中我们证明了复方阵的一种分解的唯一性，并给出了这种唯一分解的几个应用。