Results 21 to 30 of about 41,274 (203)

A New Algorithm for Positive Semidefinite Matrix Completion

open access: yesJournal of Applied Mathematics, 2016
Positive semidefinite matrix completion (PSDMC) aims to recover positive semidefinite and low-rank matrices from a subset of entries of a matrix. It is widely applicable in many fields, such as statistic analysis and system control.
Fangfang Xu, Peng Pan
doaj   +1 more source

A counterexample to the Drury permanent conjecture

open access: yesSpecial Matrices, 2017
We offer a counterexample to a conjecture concerning the permanent of positive semidefinite matrices. The counterexample is a 4 × 4 complex correlation matrix.
Hutchinson George
doaj   +1 more source

Hilbert’s 17th problem in free skew fields

open access: yesForum of Mathematics, Sigma, 2020
This paper solves the rational noncommutative analogue of Hilbert’s 17th problem: if a noncommutative rational function is positive semidefinite on all tuples of Hermitian matrices in its domain, then it is a sum of Hermitian squares of noncommutative ...
Jurij Volčič
doaj   +1 more source

A Characterization on Singular Value Inequalities of Matrices

open access: yesJournal of Function Spaces, 2020
We obtain a characterization of pair matrices A and B of order n such that sjA≤sjB, j=1, …, n, where sjX denotes the j-th largest singular values of X. It can imply not only some well-known singular value inequalities for sums and direct sums of matrices
Wei Dai, Yongsheng Ye
doaj   +1 more source

Positive Maps and Separable Matrices

open access: yes, 2016
A linear map between real symmetric matrix spaces is positive if all positive semidefinite matrices are mapped to positive semidefinite ones. A real symmetric matrix is separable if it can be written as a summation of Kronecker products of positive ...
Nie, Jiawang, Zhang, Xinzhen
core   +1 more source

有关矩阵广义逆的惯性指数及其应用(Inertia formulae related to the generalized inverse with applications)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2019
In this paper, firstly, we establish the inertia formulae for some matrix expressions related to the generalized inverse . Then, as applications, based on the derived inertia formulae, we study the definiteness of some matrices.
WUZhongcheng(吴中成)   +1 more
doaj   +1 more source

Generic Spectrahedral Shadows [PDF]

open access: yes, 2015
Spectrahedral shadows are projections of linear sections of the cone of positive semidefinite matrices. We characterize the polynomials that vanish on the boundaries of these convex sets when both the section and the projection are generic.Comment ...
Sinn, Rainer, Sturmfels, Bernd
core   +1 more source

The resolvent average for positive semidefinite matrices

open access: yesLinear Algebra and its Applications, 2010
We define a new average - termed the resolvent average - for positive semidefinite matrices. For positive definite matrices, the resolvent average enjoys self-duality and it interpolates between the harmonic and the arithmetic averages, which it approaches when taking appropriate limits. We compare the resolvent average to the geometric mean.
Bauschke, Heinz H.   +2 more
openaire   +3 more sources

Measuring Sphericity in Positive Semi-Definite Matrices

open access: yesAxioms
The measure of sphericity for positive semi-definite matrices plays a crucial role in understanding their geometric properties, especially in high-dimensional settings.
Dário Ferreira, Sandra S. Ferreira
doaj   +1 more source

A new look at nonnegativity on closed sets and polynomial optimization [PDF]

open access: yes, 2011
We first show that a continuous function f is nonnegative on a closed set $K\subseteq R^n$ if and only if (countably many) moment matrices of some signed measure $d\nu =fd\mu$ with support equal to K, are all positive semidefinite (if $K$ is compact $\mu$
Lasserre, Jean B.
core   +3 more sources

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