Enumeration of symmetry classes of alternating sign matrices and characters of classical groups

An alternating sign matrix is a square matrix with entries 1, 0 and −1 such that the sum of the entries in each row and each column is equal to 1 and the nonzero entries alternate in sign along each row and each column. To some of the symmetry classes of alternating sign matrices and their variations, G. Kuperberg associate square ice models with appropriate boundary conditions, and give determinant and Pfaffian formulae for the partition functions. In this paper, we utilize several determinant and Pfaffian identities to evaluate Kuperberg's determinants and Pfaffians, and express the round partition functions in terms of irreducible characters of classical groups. In particular, we settle a conjecture on the number of vertically and horizontally symmetric alternating sign matrices (VHSASMs). Dedicated to the memory of David Robbins.     

布尔矩阵的指标格的性质

介绍了布尔矩阵的行零元、列零元和相容子矩阵的定义并讨论了它们的性质,给出了布尔矩阵的指标格分别为分配格、半分配格和半模格的等价条件.     

On Integer Solutions to Linear Equations

A magic square is an n × n matrix with non-negative integer entries, such that the sum of the entries in each row and column is the same. We study the enumeration and P-recursivity of these in the case in which the sum along each row and column is fixed, with the size n of the matrix as the variable. A method is developed that nicely proves some known results about the case when the row and column sum is 2, and we prove new results for the case when the sum is 3. Received December 23, 2005     

A sign test for detecting the equivalence of Sylvester Hadamard matrices

In this paper we show that every matrix in the class of Sylvester Hadamard matrices of order 2 ^k under H-equivalence can have full row and column sign spectrum, meaning that tabulating the numbers of sign interchanges along any row (or column) gives all integers 0,1,...,2 ^k  − 1 in some order. The construction and properties of Yates Hadamard matrices are presented and is established their equivalence with the Sylvester Hadamard matrices of the same order. Finally, is proved that every normalized Hadamard matrix has full column or row sign spectrum if and only if is H-equivalent to a Sylvester Hadamard matrix. This provides us with an efficient criterion identifying the equivalence of Sylvester Hadamard matrices.     

Construction of Normal Bimagic Squares of Order 2u

Acta Mathematicae Applicatae Sinica, English Series - An n × n matrix A consisting of nonnegative integers is a general magic square of order n if the sum of elements in each row, column, and...     

Generalized fuzzy matrices

We give a systematic development of fuzzy matrix theory. Many of our results generalize to matrices over the two element Boolean algebra, over the nonnegative real numbers, over the nonnegative integers, and over the semirings, and we present these generalizations. Our first main result is that while spaces of fuzzy vectors do not have a unique basis in general they have a unique standard basis, and the cardinality of any two bases are equal. Thus concepts of row and column basis, row and column rank can be defined for fuzzy matrices. Then we study Green's equivalence classes of fuzzy matrices. New we give criteria for a fuzzy matrix to be regular and prove that the row and column rank of any regular fuzzy matrix are equal. Various inverses are also studied. In the next section, we obtain bounds for the index and period of a fuzzy matrix.     

Distributions of eigenvalues and inertias of some block Hermitian matrices consisting of orthogonal projectors

A complex square matrix A is called an orthogonal projector if A ²?=?A?=?A*, where A* is the conjugate transpose of A. In this article, we first give some formulas for calculating the distributions of real eigenvalues of a linear combination of two orthogonal projectors. Then, we establish various expansion formulas for calculating the inertias, ranks and signatures of some 2?×?2 and 3?×?3, as well as k?×?k block Hermitian matrices consisting of two orthogonal projectors. Many applications of the formulas are presented in characterizing interval distributions of numbers of eigenvalues, and nonsingularity of these block Hermitian matrices. In addition, necessary and sufficient conditions are given for various equalities and inequalities of these block Hermitian matrices to hold.     

On the theory of Pfaffians based on exponential maps in exterior algebras

Based on the relation of exponential maps and interior products in exterior algebras, some formulas of Pfaffians, including expansion formulas and the Cayley-Jacobi formula for determinants of alternating matrices, are deduced with new proofs. As an application, Pfaffian powers of alternating bilinear forms [O. Loos, Discriminant algebras and adjoints of quadratic forms, Beiträge Algebra Geom. 38 (1997) 33-72] are interpreted in terms of exponential maps in algebras of alternating multi-linear forms.     

Matrix pencils completion problems

In this paper we give a partial solution to the challenge problem posed by Loiseau et al. in [J. Loiseau, S. Mondié, I. Zaballa, P. Zagalak, Assigning the Kronecker invariants of a matrix pencil by row or column completion, Linear Algebra Appl. 278 (1998) 327-336], i.e. we assign the Kronecker invariants of a matrix pencil obtained by row or column completion. We have solved this problem over arbitrary fields.     

Equalities for orthogonal projectors and their operations

A complex square matrix A is called an orthogonal projector if A ² = A = A*, where A* denotes the conjugate transpose of A. In this paper, we give a comprehensive investigation to matrix expressions consisting of orthogonal projectors and their properties through ranks of matrices. We first collect some well-known rank formulas for orthogonal projectors and their operations, and then establish various new rank formulas for matrix expressions composed by orthogonal projectors. As applications, we derive necessary and sufficient conditions for various equalities for orthogonal projectors and their operations to hold.     

Line digraphs and the Moore-Penrose inverse

Various characterizations of line digraphs and of Boolean matrices possessing a Moore-Penrose inverse are used to show that a square Boolean matrix has a Moore-Penrose inverse if and only if it is the adjacency matrix of a line digraph. A similar relationship between a nonsquare Boolean matrix and a bipartite graph is also given.     

Computing the maximum generalized inverse of a Boolean matrix

This paper gives an efficient, direct method for testing whether an arbitrary Boolean matrix is regular and, if it is regular, for computing its maximum generalized inverse.     

Necessary and sufficient conditions for GMRES complete and partial stagnation

In this paper we give necessary and sufficient conditions for the complete or partial stagnation of the GMRES iterative method for solving real linear systems. Our results rely on a paper by Arioli, Pták and Strakoš (1998), characterizing the matrices having a prescribed convergence curve for the residual norms. We show that we have complete stagnation if and only if the matrix A is orthonormally similar to an upper or lower Hessenberg matrix having a particular first row or column or a particular last row or column. Partial stagnation is characterized by a particular pattern of the matrix Q in the QR factorization of the upper Hessenberg matrix generated by the Arnoldi process.     

Cramer’s rule for some quaternion matrix equations

Cramer’s rules for some left, right and two-sided quaternion matrix equations are obtained within the framework of the theory of the column and row determinants.     

Synthesis of formulas whose complexity and depth do not exceed the asymptotically best estimates of high degree of accuracy

We study problems concerning optimal realizations of arbitrary Boolean functions by formulas in the standard basis {&;, V, ¬} in the presence of two optimality criteria: the depth and the complexity. Both the complexity and depth of Boolean functions are investigated from the point of view of so-called asymptotically best estimates of high degree of accuracy for the corresponding Shannon functions. Such estimates produce an asymptotics not only for the Shannon function, but also for the first remainder term of its standard asymptotic expansion. For any Boolean function depending on n variables, we prove that it is possible to construct a realizing formula in the basis {&;, V, ¬} so that its depth and complexity do not exceed values of the corresponding Shannon functions for the argument equal to n in the sense of asymptotic estimates of high degree of accuracy.     

Adjoints and formal adjoints of matrices of unbounded operators

In this paper we discuss diverse aspects of the mutual relationship between adjoints and formal adjoints of unbounded operators bearing a matrix structure. We emphasize the behaviour of row and column operators as they turn out to be the germs of an arbitrary matrix operator, providing most of the information about the latter as it is the troublemaker.

     

Invertibility of matrices with almost-commuting entries

In this article, formal determinants of matrices over noncommnutative rings are examined for information about matrix invertibility. In this situation determinants are of course no longer multiplicative functions. The model to be generalized is the classical theorem of Schar for matrices in block form whose blocks below the first row commute. It will be seen that Schur's theorem holds over a very wide class of rings for matrices of arbitrary size. Additionally, the results provide a test for a matrix to be a non zero divisor; and by symmetry a permanental condition for invertibility of certain matrices is obtained.     

Recognizing Balanceable Matrices

A 0/±1 matrix is balanced if it does not contain a square submatrix with exactly two nonzero entries per row and per column in which the sum of all entries is 2 modulo 4. A 0/1 matrix is balanceable if its nonzero entries can be signed ±1 so that the resulting matrix is balanced. A signing algorithm due to Camion shows that the problems of recognizing balanced 0/±1 matrices and balanceable 0/1 matrices are equivalent. Conforti, Cornuéjols, Kapoor and Vušković gave an algorithm to test if a 0/±1 matrix is balanced. Truemper has characterized balanceable 0/1 matrices in terms of forbidden submatrices. In this paper we give an algorithm that explicitly finds one of these forbidden submatrices or shows that none exists. Received: October 2004     

On Binary Resilient Functions

Using a lifting formula for the coefficients of Boolean functions, we characterize binary resilient functions as binary matrices with certain row or column intersection properties. We give some new constructions of binary resilient functions based on this characterization. In particular, we show that the incidence matrix of a Steiner system can be used to construct binary resilient functions.     

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.