Results 21 to 30 of about 41,020 (249)

Conic approach to quantum graph parameters using linear optimization over the completely positive semidefinite cone [PDF]

open access: yes, 2015
We investigate the completely positive semidefinite cone $\mathcal{CS}_+^n$, a new matrix cone consisting of all $n\times n$ matrices that admit a Gram representation by positive semidefinite matrices (of any size).
Laurent, Monique, Piovesan, Teresa
core   +3 more sources

On the cone of positive semidefinite matrices

open access: yesLinear Algebra and its Applications, 1987
AbstractA survey of some general properties of the cone of positive semidefinite matrices, its faces, two isometric isomorphisms, and linear transformations on it is given.
Steven R. Waters, Richard D. Hill
openaire   +2 more sources

A class of positive semidefinite matrices

open access: yesLinear Algebra and its Applications, 1987
AbstractA matrix [aij(α)xij] is shown to be positive semidefinite or positive definite if the matrix [xij] is positive semidefinite or positive definite and aij(α) belongs to a large class of functions of α. This class includes the reciprocals of the αth mean values of xii and xjj in the cases where xii, xjj, and α are all positive.
A.M. Russell, C.J.F. Upton
openaire   +2 more sources

An elementary proof of Chollet’s permanent conjecture for 4 × 4 real matrices

open access: yesSpecial Matrices, 2021
A proof of the statement per(A ∘ B) ≤ per(A)per(B) is given for 4 × 4 positive semidefinite real matrices. The proof uses only elementary linear algebra and a rather lengthy series of simple inequalities.
Hutchinson George
doaj   +1 more source

On the closure of the completely positive semidefinite cone and linear approximations to quantum colorings [PDF]

open access: yes, 2015
We investigate structural properties of the completely positive semidefinite cone $\mathcal{CS}_+^n$, consisting of all the $n \times n$ symmetric matrices that admit a Gram representation by positive semidefinite matrices of any size. This cone has been
Burgdorf, Sabine   +2 more
core   +5 more sources

On a product of positive semidefinite matrices

open access: yesLinear Algebra and its Applications, 1999
AbstractNecessary and sufficient conditions are given for the product of two positive semidefinite (psd) matrices to be EP. As a consequence, it is shown that the product of two psd matrices is psd if and only if the product is normal.
C. Rajian, A.R. Meenakshi
openaire   +2 more sources

Analysis of Fixing Nodes Used in Generalized Inverse Computation

open access: yesAdvances in Electrical and Electronic Engineering, 2014
In various fields of numerical mathematics, there arises the need to compute a generalized inverse of a symmetric positive semidefinite matrix, for example in the solution of contact problems.
Pavla Hruskova
doaj   +1 more source

Poisson Quantum Information [PDF]

open access: yesQuantum, 2021
By taking a Poisson limit for a sequence of rare quantum objects, I derive simple formulas for the Uhlmann fidelity, the quantum Chernoff quantity, the relative entropy, and the Helstrom information.
Mankei Tsang
doaj   +1 more source

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

Positive Semidefinite Matrices, Exponential Convexity for Majorization, and Related Cauchy Means

open access: yesJournal of Inequalities and Applications, 2010
We prove positive semidefiniteness of matrices generated by differences deduced from majorization-type results which implies exponential convexity and log-convexity of these differences and also obtain Lyapunov's and Dresher's inequalities for these ...
Latif N, Pečarić J, Anwar M
doaj   +2 more sources

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