Results 51 to 60 of about 49,656 (213)
An elementary proof of Chollet’s permanent conjecture for 4 × 4 real matrices
Special 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
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AIMS Mathematics, 2023 We extend the notion of classical metric geometric mean (MGM) for positive definite matrices of the same dimension to those of arbitrary dimensions, so that usual matrix products are replaced by semi-tensor products.
Arnon Ploymukda, Pattrawut Chansangiam
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Computing a nearest symmetric positive semidefinite matrix
Linear Algebra and its Applications, 1988 The problem of computing a nearest positive semidefinite matrix (notation used \(X\geq 0)\) to an arbitrary real matrix A is considered. The criterion of approximation is the distance \(\delta (A)=\min_{X=X^ T\geq 0}\| A-X\|\) where the norm is chosen to be either Frobenius or 2-norm. The paper consists of two parts. In the first part the author proves
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Planning and Control Framework for a Quadruped Robot With Changeable Configuration
Advanced Intelligent Systems, EarlyView.Multiconfiguration quadruped robots enhance adaptability by switching between mammal‐like and reptile‐like morphologies. This study presents a nonlinear constraint‐based motion planner integrated with a hierarchical whole‐body controller, enabling robust configuration switching and locomotion on complex terrains. Experiments on slopes, irregular bricks,
Guanglin Lu +5 more
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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)
Zhejiang 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
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Degree theory for 4‐dimensional asymptotically conical gradient expanding solitons
Communications on Pure and Applied Mathematics, EarlyView.Abstract We develop a new degree theory for 4‐dimensional, asymptotically conical gradient expanding solitons. Our theory implies the existence of gradient expanding solitons that are asymptotic to any given cone over S3$S^3$ with non‐negative scalar curvature. We also obtain a similar existence result for cones whose link is diffeomorphic to S3/Γ$S^3/\
Richard H. Bamler, Eric Chen
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Purifications of multipartite states: limitations and constructive methods
New 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
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Convergence analysis of the information matrix in Gaussian belief propagation [PDF]
, 2017 Gaussian belief propagation (BP) has been widely used for distributed estimation in large-scale networks such as the smart grid, communication networks, and social networks, where local measurements/observations are scattered over a wide geographical ...
Du, Jian +4 more
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A Deep Learning Framework for Forecasting Medium‐Term Covariance in Multiasset Portfolios
Journal of Forecasting, EarlyView.ABSTRACT Forecasting the covariance matrix of asset returns is central to portfolio construction, risk management, and asset pricing. However, most existing models struggle at medium‐term horizons, several weeks to months, where shifting market regimes and slower dynamics prevail.
Pedro Reis, Ana Paula Serra, João Gama
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Low rank approximation of the symmetric positive semidefinite matrix
Journal of Computational and Applied Mathematics, 2014 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Duan, Xuefeng +3 more
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