Kronecker products and BIBDs

Recursive constructions are given which permit, under conditions described in the paper, a (v, b, r, k, λ)-configuration to be used to obtain a (v′, b′, r′, k, λ)-configuration.     

向量交换矩阵一种新的定义及应用

利用单位矩阵和基本向量给出了向量交换矩阵的一种较以往表述简单的新的定义.基于新的定义证明了向量交换矩阵的性质.给出了新定义与原有定义的等价性的证明.最后给出了矩阵克罗内克积奇异值的一个新的结论.     

The exponent of a polarizing matrix constructed from the Kronecker product

It was recently shown by Korada et al. that the partial distances of a polarizing matrix completely determine its exponent characterizing the asymptotic performance of a polar code under successive cancellation decoding. In this paper we prove in a purely algebraic way that the partial distances of a polarizing matrix constructed from the Kronecker product are simply expressed as a product of those of its component matrices. As a result, the exponent of the polarizing matrix is shown to be a weighted sum of the exponents of its component matrices.     

Spline approximation,Kronecker products and multilinear forms

Sums of Kronecker products occur naturally in high‐dimensional spline approximation problems, which arise, for example, in the numerical treatment of chemical reactions. In full matrix form, the resulting non‐sparse linear problems usually exceed the memory capacity of workstations. We present methods for the manipulation and numerical handling of Kronecker products in factorized form. Moreover, we analyze the problem of approximating a given matrix by sums of Kronecker products by making use of the equivalence to the problem of decomposing multilinear forms into sums of one‐forms. Greedy algorithms based on the maximization of multilinear forms over a torus are used to obtain such (finite and infinite) decompositions that can be used to solve the approximation problem. Moreover, we present numerical considerations for these algorithms. Copyright © 2016 John Wiley & Sons, Ltd.     

Kronecker type theorems,normality and continuity of the multivariate Padé operator

Summary. For univariate functions the Kronecker theorem, stating the equivalence between the existence of an infinite block in the table of Padé approximants and the approximated function being rational, is well-known. In [Lubi88] Lubinsky proved that if is not rational, then its Padé table is normal almost everywhere: for an at most countable set of points the Taylor series expansion of is such that it generates a non-normal Padé table. This implies that the Padé operator is an almost always continuous operator because it is continuous when computing a normal Padé approximant [Wuyt81]. In this paper we generalize the above results to the case of multivariate Padé approximation. We distinguish between two different approaches for the definition of multivariate Padé approximants: the general order one introduced in [Levi76, CuVe84] and the so-called homogeneous one discussed in [Cuyt84]. Received December 19, 1994     

Solutions to a family of matrix equations by using the Kronecker matrix polynomials

Closed form solutions to a family of generalized Sylvester matrix equation in form of are given by using the so-called Kronecker matrix polynomials. It is found that the structure of the solutions is independent of the orders ?,ψ and φ. This type of uniform closed form solutions includes our early results as special cases. The results provide great convenience to the computation and analysis of the solutions to this class of equations, and can perform important functions in many analysis and design problems in linear systems.     

Unsolved problems in matrix and operator theory,II. partial multiplicities for products

The purpose of this note is to pose a problem about the partial multiplicities of a product of two matrix polynomials given those of its factors.     

Trace cocharacters and the Kronecker products of Schur functions

It follows from the theory of trace identities developed by Procesi and Razmyslov that the trace cocharacters arising from the trace identities of the algebra M_r(F) of r×r matrices over a field F of characteristic zero are given by TC_r,n=∑_λΛr(n)χ^λχ^λ where χ^λχ^λ denotes the Kronecker product of the irreducible characters of the symmetric group associated with the partition λ with itself and Λ_r(n) denotes the set of partitions of n with r or fewer parts, i.e. the set of partitions λ=(λ₁λ_k) with kr. We study the behavior of the sequence of trace cocharacters TC_r,n. In particular, we study the behavior of the coefficient of χ^(ν,n−m) in TC_r,n as a function of n where ν=(ν₁ν_k) is some fixed partition of m and n−mν_k. Our main result shows that such coefficients always grow as a polynomial in n of degree r−1.     

Exponential functions of Kronecker products and trace calculation

An identity for the trace of an exponential function of Kronecker products of matrices is derived. This identity is important for the calculation of the grand potential for Fermi systems.     

On a second-order matrix differential operator

We consider the second-order matrix differential operator $$N = \left( {\begin{array}{*{20}c} { - \frac{d}{{dx}}\left( {p_0 \frac{d}{{dx}}} \right) + p_1 } \\ r \\ \end{array} \begin{array}{*{20}c} r \\ { - \frac{d}{{dx}}\left( {q_0 \frac{d}{{dx}}} \right) + q_1 } \\ \end{array} } \right)$$ determined by the expression Nφ, [0 ?x < ∞), where \(\phi = \left( {\begin{array}{*{20}c} U \\ V \\ \end{array} } \right)\) . It has been proved that if p₀, q₀, p₁, q₁,r satisfy certain conditions, then N is in the limit point case at ∞. It has been also shown that certain differential operators in the Hilbert space L² of vectors, generated by the operator N, are symmetric and self-adjoint.     

Multiplication operator on a matrix polynomial

It is proved that the study of a perturbed multiplication operator on a matrix polynomial in the space L₂(, ⁿ) may be reduced to the study of a perturbed multiplication operator with independent variable in the space L₂(, , ^N) with weight satisfying the Mackenhaupt condition.Translated from Ukrayins'kyy Matemarychnyy Zhurnal, Vol. 44, No. 9, pp. 1287–1289, September, 1992.     

Characterizations of sums of dyads and of Kronecker products

This research was partially supported by Air Force Office of Scientific Research Grant 75-2858.     

Some rank equalities and inequalities for Kronecker products of matrices

A set of rank equalities and inequalities are established for block matrices consisting of Kronecker products. Various consequences are also given.     

Generalized Jordan matrix of a linear operator

For any linear operator defined over an arbitrary field k, there is a basis in which this matrix is a generalized Jordan matrix (of the second kind) with elements in the field k. For any linear operator, such a matrix is defined uniquely up to permutation of diagonal blocks.     

On Hill's operator with a matrix potential

In this article we obtain asymptotic formulas for eigenvalues and eigenfunctions of the self‐adjoint operator generated by a system of Sturm–Liouville equations with summable coefficients and quasiperiodic boundary conditions. Then using these asymptotic formulas, we find conditions on the potential for which the number of gaps in the spectrum of the Hill's operator with matrix potential is finite. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the number of eigenvalues of a matrix operator

We consider a matrix operator H in the Fock space. We prove the finiteness of the number of negative eigenvalues of H if the corresponding generalized Friedrichs model has the zero eigenvalue (0 = min σ _ess(H)). We also prove that H has infinitely many negative eigenvalues accumulating near zero (the Efimov effect) if the generalized Friedrichs model has zero energy resonance. We obtain asymptotics for the number of negative eigenvalues of H below z as z → −0.     

Study of the essential spectrum of a matrix operator

We consider a matrix operator H corresponding to a system with a nonconserved finite number of particles on a lattice. We describe the structure of the essential spectrum of the operator H and prove that the essential spectrum is a union of at most four intervals.     

Some rank equalities and inequalities for Kronecker products of matrices

A set of rank equalities and inequalities are established for block matrices consisting of Kronecker products. Various consequences are also given.