Results 91 to 100 of about 54,917 (203)

Leaky positive semidefinite forcing on graphs

open access: yesInvolve, a Journal of Mathematics
We introduce $\ell$-leaky positive semidefinite forcing and the $\ell$-leaky positive semidefinite number of a graph, $Z_{(\ell)}^+{G}$, which combines the positive semidefinite color change rule with the addition of leaks to the graph. Furthermore, we determine general properties of $Z_{(\ell)}^+{G}$ and $Z_{(\ell)}^+{G}$ for various graphs, including
Elias, Olivia   +4 more
openaire   +3 more sources

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

On the asymptotic Bieberbach conjecture

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1982
The set S consists of complex functions f, univalent in the open unit disk, with f(0)=f'(0)-1=0. We use the asymptotic behavior of the positive semidefinite FitzGerald matrix to show that there is an absolute constant N0 such that, for any f(z)=z+?n ...
Mauriso Alves, Armando J. P. Cavalcante
doaj   +1 more source

Purifications of multipartite states: limitations and constructive methods

open access: yesNew Journal of Physics, 2013
We analyze the description of quantum many-body mixed states using matrix product states and operators. We consider two such descriptions: (i) as a matrix product density operator of bond dimension D ; and (ii) as a purification that is written as a ...
Gemma De las Cuevas   +3 more
doaj   +1 more source

Correcting for finite statistics effects in a quantum steering experiment

open access: yesPhysical Review Research
Verifying entanglement between parties is essential for creating secure quantum communication. However, finite statistics can lead to false positive outcomes in any tests for entanglement.
Sophie Engineer   +9 more
doaj   +1 more source

Symmetric Positive Semi-Definite Fourier Estimator of Spot Covariance Matrix with High Frequency Data

open access: yesRisks
This paper proposes a nonparametric estimator of the spot volatility matrix with high-frequency data. Our newly proposed Positive Definite Fourier (PDF) estimator produces symmetric positive semi-definite estimates and is consistent with a suitable ...
Jiro Akahori   +5 more
doaj   +1 more source

A sequential semidefinite programming method and an application in passive reduced-order modeling

open access: yes, 2005
We consider the solution of nonlinear programs with nonlinear semidefiniteness constraints. The need for an efficient exploitation of the cone of positive semidefinite matrices makes the solution of such nonlinear semidefinite programs more complicated ...
Freund, Roland W.   +2 more
core  

Regression on fixed-rank positive semidefinite matrices: a Riemannian approach [PDF]

open access: yes, 2011
The paper addresses the problem of learning a regression model parameterized by a fixed-rank positive semidefinite matrix. The focus is on the nonlinear nature of the search space and on scalability to high-dimensional problems.
Bonnabel, Silvere   +2 more
core  

Hyperbolic Polynomials and Generalized Clifford Algebras [PDF]

open access: yes, 2012
We consider the problem of realizing hyperbolicity cones as spectrahedra, i.e. as linear slices of cones of positive semidefinite matrices. The generalized Lax conjecture states that this is always possible. We use generalized Clifford algebras for a new
Netzer, Tim, Thom, Andreas
core   +1 more source

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