Results 41 to 50 of about 71,800 (235)

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

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

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

Conditions for Existence of Dual Certificates in Rank-One Semidefinite Problems [PDF]

open access: yes, 2014
Several signal recovery tasks can be relaxed into semidefinite programs with rank-one minimizers. A common technique for proving these programs succeed is to construct a dual certificate.
Hand, Paul
core   +1 more source

Experimental Joint Estimation of Phase and Phase Diffusion Via Deterministic Bell Measurements

open access: yesAdvanced Science, EarlyView.
This work employs Bell measurement, a form of entangling measurement, to estimate both the phase and its fluctuations in an optical interferometer. By incorporating a novel quantum effect at the measurement stage, the proposed method achieves the ultimate precision limit and demonstrates the significant potential of entangling measurements in multi ...
Ben Wang   +4 more
wiley   +1 more source

GBD and $ \mathcal{L} $-positive semidefinite elements in $ C^* $-algebras

open access: yesAIMS Mathematics
This paper focused on the generalized Bott-Duffin (GBD) inverse and the $ {\rm GBD} $ elements in Banach algebra with involution and $ C^* $-algebra, as well as on the property of the $ p $-positive semidefinite elements that are a generalization of the $
Kezheng Zuo   +2 more
doaj   +1 more source

Using distance on the Riemannian manifold to compare representations in brain and in models

open access: yesNeuroImage, 2021
Representational similarity analysis (RSA) summarizes activity patterns for a set of experimental conditions into a matrix composed of pairwise comparisons between activity patterns.
Mahdiyar Shahbazi   +3 more
doaj   +1 more source

A Unique "Nonnegative" Solution to an Underdetermined System: from Vectors to Matrices [PDF]

open access: yes, 2009
This paper investigates the uniqueness of a nonnegative vector solution and the uniqueness of a positive semidefinite matrix solution to underdetermined linear systems.
Ao Tang   +3 more
core   +3 more sources

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