Results 71 to 80 of about 808,716 (283)

On Positive Definiteness of Some Functions

Journal of Multivariate Analysis, 2000
Let \(E\) be a linear space over \(\mathbb{R}\) and let \(\rho(x)\) be the \(\ell^n_p\)-norm in \(\mathbb{R}^n\). A function \(f: E\to\mathbb{C}\) is called definite if \(\sum^n_{k,j=1} c_k\overline c_jf(x_k- x_j)\geq 0\) for all \(n\in\mathbb{N}\), \(x_k\in E\), \(c_k\in\mathbb{C}\) for \(k= 1,2,\dots, n\).
openaire   +4 more sources

Fundamental Challenges, Physical Implementations, and Integration Strategies for Ising Machines in Large‐Scale Optimization Tasks

Advanced Electronic Materials, EarlyView.
Ising machines are emerging as specialized hardware solvers for computationally hard optimization problems. This review examines five major platforms—digital CMOS, analog CMOS, emerging devices, coherent optics, and quantum systems—highlighting physics‐rooted advantages and shared bottlenecks in scalability and connectivity.
Hyunjun Lee, Joon Pyo Kim, Sanghyeon Kim
wiley   +1 more source

NEW PROPOSED METHODS FOR CODING INFORMATION USING DIRECT PRODUCT OF SYMMETRIC MATRICES AND CONTRACTION FUNCTIONS WITH NEW PROPERTIES OF HERMITIAN MATRICES

Journal of Kufa for Mathematics and Computer, 2010
In this paper, two separately methods were suggested for coding information .The first method was introduced using the directness of symmetric matrices .The contraction function was used for introducing the second method .For more complexity the ...
Adel Mohammad Hassan Rizak Al-Rammahi
doaj   +1 more source

Metric spaces and positive definite functions [PDF]

Transactions of the American Mathematical Society, 1938
As poo we get the space Em with the distance function maxi-, ... I xi X. Let, furthermore, lP stand for the space of real sequences with the series of pth powers of the absolute values convergent. Similarly let LP denote the space of real measurable functions in the interval (0, 1) which are summable to the pth power, while C shall mean the space of ...
openaire   +3 more sources

Asymmetric Multi‐Site Ion Exchange in Porous Carbon Electrodes

Advanced Energy Materials, EarlyView.
A lognormal‐distribution 2D EXSY NMR framework uncovers the full spectrum of ion dynamics in hierarchical porous carbons, bridging fast surface exchange and confined in‐pore transport—establishing structure–transport relationships for next‐generation energy storage, gas storage, and ion removal materials.
Henry R. N. B. Enninful, Marius Hermesdorf, Muhammad Abdullah Khan, Desirée Leistenschneider, Martin Oschatz, Rustem Valiullin   +5 more
wiley   +1 more source

On the stability of third order differential equations

Журнал Белорусского государственного университета: Математика, информатика, 2019
In this paper, we study the problem of stability of the equilibrium of nonlinear ordinary differential equations by the method of semi-definite Lyapunov’s functions.
Boris S. Kalitine
doaj  

New concepts of fractional Hahn’s q,ω $q,\omega $-derivative of Riemann–Liouville type and Caputo type and applications

Advances in Difference Equations, 2018
In this paper, we give the definitions of q,ω $q,\omega $-exponential function and q,ω $q,\omega $-gamma function. New concepts of fractional Hahn’s q,ω $q,\omega $-derivative of Riemann–Liouville type and Caputo type are introduced, meanwhile we discuss
Yizhu Wang, Yiding Liu, Chengmin Hou
doaj   +1 more source

Message-Passing Algorithms for Quadratic Minimization

, 2012
Gaussian belief propagation (GaBP) is an iterative algorithm for computing the mean of a multivariate Gaussian distribution, or equivalently, the minimum of a multivariate positive definite quadratic function.
Ruozzi, Nicholas, Tatikonda, Sekhar
core  

Circularity, Sustainability, and the Quality of Coffee Sold via Vending Machines: What Do Italian Consumers Prefer?

Agribusiness, EarlyView.
ABSTRACT Vending is an important sector in the daily lives of many people, and coffee is the most frequently consumed product in the European market. Like many other sectors, vending is responding to the challenge of sustainable development by taking various actions, such as offering increasingly ecologically sound coffee while maintaining/improving ...
Alberto Bertossi, Stefania Troiano, Francesco Marangon   +2 more
wiley   +1 more source

The Maximal Regularity of Nonlinear Second-Order Hyperbolic Boundary Differential Equations

Axioms
In this paper, we show the maximal regularity of nonlinear second-order hyperbolic boundary differential equations. We aim to show if the given second-order partial differential operator satisfies the specific ellipticity condition; additionally, if ...
Xingyu Liu
doaj   +1 more source