关于一个半正定矩阵的Khatri-Rao乘积的不等式的讨论

得到的一个矩阵乘积不等式及其逆向不等式．应用这些结果，把一个半正定矩阵Khatri-Rao乘积的不等式推广到实对称矩阵．并给出了它的逆向不等式及其等式条件．     

广义实正定矩阵的几个不等式

推广了文献[3]中的广义实正定矩阵的行列式不等式,同时给出了广义实正定矩阵的凸性不等式.     

Rearrangement inequalities for Hermitian matrices

Hermitian matrices can be thought of as generalizations of real numbers. Many matrix inequalities, especially for Hermitian matrices, are derived from their scalar counterparts. In this paper, the Hardy-Littlewood-Pólya rearrangement inequality is extended to Hermitian matrices with respect to determinant, trace, Kronecker product, and Hadamard product.     

Reverse Young and Heinz inequalities for matrices

We give reverses of the classical Young inequality for positive real numbers and we use these to establish reverse Young and Heinz inequalities for matrices.     

Improved Young and Heinz inequalities for matrices

We give refinements of the classical Young inequality for positive real numbers and we use these refinements to establish improved Young and Heinz inequalities for matrices.     

Enhancements to the von Neumann trace inequality

Upper trace bounds for the product of two n × n complex matrices are presented. The real component of the trace inequality is tighter than von Neumann’s inequality, and the imaginary component is new.     

On a generalized Fan inequality

It is shown that the ω- and τ-matrices, the weakly sign symmetric matrices, the R- and V-matrices, and the matrices c-equivalent to an M-matrix or to a real matrix with nonpositive off-diagonal elements, can all be characterized by the same determinantal inequality, which we call a generalized Fan inequality.     

对称部分为半正定的方阵

所有ｎ阶具有半正定对称部分的方阵的集合记作ＰＳＤｎ．本文给出了ＰＳＤｎ中方阵在合同下的标准形以及ＰＳＤｎ中两个方阵合同的一个充要条件，并给出了ＰＳＤｎ中一个方阵及其对称部分与斜对称部分的主子式间的一个不等式．     

Row Stochastic Matrices Similar to Doubly Stochastic Matrices

The problem of determining which row stochastic n-by-n matrices are similar to doubly stochastic matrices is considered. That not all are is indicated by example, and an abstract characterization as well as various explicit sufficient conditions are given. For example, if a row stochastic matrix has no entry smaller than (n+1)^-1 it is similar to a doubly stochastic matrix.

Relaxing the nonnegativity requirement, the real matrices which are similar to real matrices with row and column sums one are then characterized, and it is observed that all row stochastic matrices have this property. Some remarks are then made on the nonnegative eigenvalue problem with respect to i) a necessary trace inequality and ii) removing zeroes from the spectrum.     

DDVV-type inequality for skew-symmetric matrices and Simons-type inequality for Riemannian submersions

In this paper, we will first derive a DDVV-type optimal inequality for real skew-symmetric matrices, then we apply it to establish a Simons-type integral inequality for Riemannian submersions with totally geodesic fibres and Yang–Mills horizontal distributions. In this way, we show phenomenons of duality between submanifold geometry and Riemannian submersion, particularly between second fundamental form of a submanifold and integrability tensor of a Riemannian submersion.     

On the Meany inequality with applications to convergence analysis of several row-action iteration methods

The Meany inequality gives an upper bound in the Euclidean norm for a product of rank-one projection matrices. In this paper we further derive a lower bound related to this inequality. We discuss the internal relationship between the upper bounds given by the Meany inequality and by the inequality in Smith et al. (Bull Am Math Soc 83:1227–1270, 1977) in the finite dimensional real linear space. We also generalize the Meany inequality to the block case. In addition, by making use of the block Meany inequality, we improve existing results and establish new convergence theorems for row-action iteration schemes such as the block Kaczmarz and the Householder–Bauer methods used to solve large linear systems and least-squares problems.     

A Cauchy--Khinchin--van Dam matrix inequality

We derive a matrix inequality, which generalizes the Cauchy inequality for vectors, Khinchin's inequality for zero-one matrices and van Dam's inequality for matrices.     

Distribution of Eigenvalues of Real Symmetric Palindromic Toeplitz Matrices and Circulant Matrices

Consider the ensemble of real symmetric Toeplitz matrices, each independent entry an i.i.d. random variable chosen from a fixed probability distribution p of mean 0, variance 1, and finite higher moments. Previous investigations showed that the limiting spectral measure (the density of normalized eigenvalues) converges weakly and almost surely, independent of p, to a distribution which is almost the standard Gaussian. The deviations from Gaussian behavior can be interpreted as arising from obstructions to solutions of Diophantine equations. We show that these obstructions vanish if instead one considers real symmetric palindromic Toeplitz matrices, matrices where the first row is a palindrome. A similar result was previously proved for a related circulant ensemble through an analysis of the explicit formulas for eigenvalues. By Cauchy’s interlacing property and the rank inequality, this ensemble has the same limiting spectral distribution as the palindromic Toeplitz matrices; a consequence of combining the two approaches is a version of the almost sure Central Limit Theorem. Thus our analysis of these Diophantine equations provides an alternate technique for proving limiting spectral measures for certain ensembles of circulant matrices. A. Massey’s current address: Department of Mathematics, UCLA, Los Angeles, CA 90095, USA. e-mail: amassey3102@math.ucla.edu.     

An extension of Harnack type determinantal inequality

We revisit and comment on the Harnack type determinantal inequality for contractive matrices obtained by Tung in the nineteen sixties and give an extension of the inequality involving multiple positive semidefinite matrices .     

一个行列式不等式的进一步研究

本文的日的在于改进已有的两个复矩阵的行列式的上界,以更精细的两个Hermitian正定矩阵和的行列式为基本工具.利用得到的相关一无二次不等式描述的行列式之间的关系,给出了两个复矩阵和的行列式新上界,作为心用可改进华罗庚行列式不等式的上界.     

Interpolating inequalities related to a recent result of Audenaert

Audenaert recently obtained an inequality for unitarily invariant norms that interpolates between the arithmetic–geometric mean inequality and the Cauchy–Schwarz inequality for matrices. A refined version of Audenaert’s inequality for the Hilbert–Schmidt norm is given. Other interpolating inequalities for unitarily invariant norms are also presented.     

A matrix trace inequality and its application

In this short paper, we give a complete and affirmative answer to a conjecture on matrix trace inequalities for the sum of positive semidefinite matrices. We also apply the obtained inequality to derive a kind of generalized Golden-Thompson inequality for positive semidefinite matrices.     

亚正定矩阵的Bergstrom型不等式

首先证明亚正定矩阵的一个偏序,利用该偏序得到了亚正定矩阵的一些Bergstrom型不等式,推广了近期关于亚正定矩阵行列式不等式的一些结果.     

The matrix valued triangle inequality:quaternion version

The matrix valued triangle inequality is shown to hold for matrices over the quaternions. The history of the inequality and open questions connected with it are described.     

关于《余A-G型Ky Fan不等式》的发展

Two new proofs of a discrete Ky Fan inequality of the comple mentary A-G type are given. Its continuous version and determinantal analogue on a set of pairwise commutative positive definite matrices are established. A further extension concerning general positive definite matrices of the inequality is also suggested.