Results 21 to 30 of about 71,699 (272)

Low-rank matrix approximations over canonical subspaces

open access: yesJournal of Numerical Analysis and Approximation Theory, 2020
In this paper we derive closed form expressions for the nearest rank-\(k\) matrix on canonical subspaces.    We start by studying three kinds of subspaces.  Let \(X\) and \(Y\) be a pair of given matrices. The first subspace contains all the \(m\times
Achiya Dax
doaj   +7 more sources

On Some Matrix Trace Inequalities

open access: yesJournal of Inequalities and Applications, 2010
We first present an inequality for the Frobenius norm of the Hadamard product of two any square matrices and positive semidefinite matrices. Then, we obtain a trace inequality for products of two positive semidefinite block matrices by using 2×2 ...
Ramazan Türkmen   +1 more
doaj   +2 more sources

A trace bound for integer-diagonal positive semidefinite matrices

open access: yesSpecial Matrices, 2020
We prove that an n-by-n complex positive semidefinite matrix of rank r whose graph is connected, whose diagonal entries are integers, and whose non-zero off-diagonal entries have modulus at least one, has trace at least n + r − 1.
Mitchell Lon
doaj   +1 more source

Separability for mixed states with operator Schmidt rank two [PDF]

open access: yesQuantum, 2019
The operator Schmidt rank is the minimum number of terms required to express a state as a sum of elementary tensor factors. Here we provide a new proof of the fact that any bipartite mixed state with operator Schmidt rank two is separable, and can be ...
Gemma De las Cuevas   +2 more
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

Decomposition of arrow type positive semidefinite matrices with application to topology optimization [PDF]

open access: yesMathematical programming, 2019
Decomposition of large matrix inequalities for matrices with chordal sparsity graph has been recently used by Kojima et al. (Math Program 129(1):33–68, 2011) to reduce problem size of large scale semidefinite optimization (SDO) problems and thus increase
M. Kočvara
semanticscholar   +1 more source

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

Sublinear Time Low-Rank Approximation of Positive Semidefinite Matrices [PDF]

open access: yesIEEE Annual Symposium on Foundations of Computer Science, 2017
We show how to compute a relative-error low-rank approximation to any positive semidefinite (PSD) matrix in sublinear time, i.e., for any n x n PSD matrix A, in Õ(n ⋅ poly(k/ε)) time we output a rank-k matrix B, in factored form, for ...
Cameron Musco, David P. Woodruff
semanticscholar   +1 more source

Fischer Type Log-Majorization of Singular Values on Partitioned Positive Semidefinite Matrices

open access: yesJournal of Function Spaces, 2021
In this paper, we establish a Fischer type log-majorization of singular values on partitioned positive semidefinite matrices, which generalizes the classical Fischer's inequality. Meanwhile, some related and new inequalities are also obtained.
Benju Wang, Yun Zhang
doaj   +1 more source

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