Results 11 to 20 of about 2,396 (56)

The Mathematical History Behind the Granger–Johansen Representation Theorem

open access: yesOxford Bulletin of Economics and Statistics, EarlyView.
ABSTRACT When can a vector time series that is integrated once (i.e., becomes stationary after taking first differences) be described in error correction form? The answer to this is provided by the Granger–Johansen representation theorem. From a mathematical point of view, the theorem can be viewed as essentially a statement concerning the geometry of ...
Johannes M. Schumacher
wiley   +1 more source

Convergence properties of dynamic mode decomposition for analytic interval maps

open access: yesCommunications on Pure and Applied Mathematics, Volume 79, Issue 2, Page 179-206, February 2026.
Abstract Extended dynamic mode decomposition (EDMD) is a data‐driven algorithm for approximating spectral data of the Koopman operator associated to a dynamical system, combining a Galerkin method with N$N$ functions and a quadrature method with M$M$ quadrature nodes.
Elliz Akindji   +3 more
wiley   +1 more source

Dissipative energy functionals of passive linear time‐varying systems

open access: yesZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, Volume 106, Issue 2, February 2026.
Abstract The concept of dissipativity plays a crucial role in the analysis of control systems. Dissipative energy functionals, also known as Hamiltonians, storage functions, or Lyapunov functions, depending on the setting, are extremely valuable to analyze and control the behavior of dynamical systems, but in general circumstances they are very ...
Riccardo Morandin, Dorothea Hinsen
wiley   +1 more source

Large‐Amplitude Periodic Solutions to the Steady Euler Equations With Piecewise Constant Vorticity

open access: yesStudies in Applied Mathematics, Volume 156, Issue 1, January 2026.
ABSTRACT We consider steady solutions to the incompressible Euler equations in a two‐dimensional channel with rigid walls. The flow consists of two periodic layers of constant vorticity separated by an unknown interface. Using global bifurcation theory, we rigorously construct curves of solutions that terminate either with stagnation on the interface ...
Alex Doak   +3 more
wiley   +1 more source

Improved Analytical Technique Based on Laplace Transform and Homotopy Perturbation Method for Solving Fractional Bratu‐Type Equations

open access: yesInternational Journal of Differential Equations, Volume 2026, Issue 1, 2026.
This study presents a modified Laplace transform homotopy perturbation method (MLT‐HPM) for obtaining approximate solutions for fractional‐order Bratu‐type ordinary differential equations involving Caputo fractional derivatives. The proposed modification introduces a specific rule for selecting the initial solution, replacing the conventional random ...
Ibrahim Hailat, Patricia J. Y. Wong
wiley   +1 more source

Study on Approximate C∗‐Bimultiplier and JC∗‐Bimultiplier in C∗‐Ternary Algebra

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2026, Issue 1, 2026.
An additive‐quadratic mapping F:A×A⟶B is one that adheres to the following equations: Fr+s,t=Fr,t+Fs,t,Fr,s+t+Fr,s−t=22Fr,s+Fr,t. This paper leverages the fixed‐point method to investigate C∗‐bimultiplier and JC∗‐bimultiplier approximations on C∗‐ternary algebras. The focus is on the additive‐quadratic functional equation: Fr+s,t+u+Fr+s,t−u=2222Fr,t+Fr,
Mina Mohammadi   +3 more
wiley   +1 more source

Understanding Measles Contagion: A Fractional‐Order Model With Stability and Sensitivity Insights

open access: yesJournal of Mathematics, Volume 2026, Issue 1, 2026.
In this paper, we propose an epidemiological mathematical model described by a system of nonlinear differential equations of fractional order (FODEs). Specifically, we employ the Caputo fractional derivative (CFD). Our analysis verifies the existence of a solution.
Mahmoud H. DarAssi   +3 more
wiley   +1 more source

Manifolds of classical probability distributions and quantum density operators in infinite dimensions

open access: yes, 2019
The manifold structure of subsets of classical probability distributions and quantum density operators in infinite dimensions is investigated in the context of $C^{*}$-algebras and actions of Banach-Lie groups.
Ciaglia, Florio M.   +3 more
core   +1 more source

Interactions between universal composition operators and complex dynamics

open access: yesJournal of the London Mathematical Society, Volume 112, Issue 3, September 2025.
Abstract This paper is concerned with universality properties of composition operators Cf$C_f$, where the symbol f$f$ is given by a transcendental entire function restricted to parts of its Fatou set. We determine universality of Cf$C_f$ when f$f$ is restricted to (subsets of) Baker and wandering domains.
Vasiliki Evdoridou   +2 more
wiley   +1 more source

2‐Adic Quantum Mechanics, Continuous‐Time Quantum Walks, and the Space Discreteness

open access: yesFortschritte der Physik, Volume 73, Issue 8, August 2025.
Abstract The authors show that a large class of 2‐adic Schrödinger equations is the scaling limit of certain continuous‐time quantum Markov chains (CTQMCs). Practically, a discretization of such an equation gives a CTQMC. As a practical result, new types of continuous‐time quantum walks (CTQWs) on graphs using two symmetric matrices are constructed ...
W. A. Zúñiga‐Galindo
wiley   +1 more source

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