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In this work we propose a new and more general approach to the calculus of variations on time scales that allows to obtain, as particular cases, both delta and nabla results. More precisely, we pose the problem of minimizing or maximizing…

最优化与控制 · 数学 2010-08-30 Ewa Girejko , Agnieszka B. Malinowska , Delfim F. M. Torres

The exponential trapezoidal rule is proposed and analyzed for the numerical integration of semilinear integro-differential equations. Although the method is implicit, the numerical solution is easily obtained by standard fixed-point…

数值分析 · 数学 2024-03-12 Alexander Ostermann , Nasrin Vaisi

Under certain general conditions, an explicit formula to compute the greatest delta-epsilon function of a continuous function is given. From this formula, a new way to analyze the uniform continuity of a continuous function is given.…

综合数学 · 数学 2017-10-12 César Adolfo Hernández Melo

The existence of exponential dichotomies has been well-established as a powerful tool to study existence, stability, and bifurcations of coherent structures. Currently, the application of exponential dichotomies to elliptic problems posed…

偏微分方程分析 · 数学 2026-03-25 Margaret Beck , Ryan Goh , Alanna Haslam-Hyde

Caputo-Fabrizio fractional delta derivatives on an arbitrary time scale are presented. When the time scale is chosen to be the set of real numbers, then the Caputo-Fabrizio fractional derivative is recovered. For isolated or partly…

经典分析与常微分方程 · 数学 2018-12-17 Dorota Mozyrska , Delfim F. M. Torres , Malgorzata Wyrwas

Let $f$ be a continuous real function defined in a subset of the real line. The standard definition of continuity at a point $x$ allow us to correlate any given epsilon with a (possibly depending of $x$) delta value. This pairing is known…

一般拓扑 · 数学 2017-10-13 Paulo M. de Carvalho-Neto , Paulo A. Liboni Filho

We study existence and regularity properties of stable positive solutions to the nonvariational problem - Delta u - b(x)|nabla u|^2 = lambda g(u) in a bounded smooth domain. In the case where b is constant, by means of a Hopf-Cole…

偏微分方程分析 · 数学 2013-10-07 Joana Terra

When scale separation in space and time is poor, the alpha effect and turbulent diffusivity have to be replaced by integral kernels. Earlier work in computing these kernels using the test-field method is now generalized to the case in which…

太阳与恒星天体物理 · 物理学 2012-01-11 M. Rheinhardt , A. Brandenburg

In this article, we investigate the existence and properties of time-periodic solutions for damped evolutionary partial differential equations subject to periodic forcing. Particular emphasis is placed on configurations where the energy…

偏微分方程分析 · 数学 2026-05-19 Camille Laurent , Ivonne Rivas

We establish some linear and nonlinear integral inequalities of Gronwall-Bellman-Bihari type for functions with two independent variables on general time scales. The results are illustrated with examples, obtained by fixing the time scales…

经典分析与常微分方程 · 数学 2009-03-06 Rui A. C. Ferreira , Delfim F. M. Torres

We consider the $\alpha$-Euler equations on a bounded three-dimensional domain with frictionless Navier boundary conditions. Our main result is the existence of a strong solution on a positive time interval, uniform in $\alpha$, for…

偏微分方程分析 · 数学 2015-09-08 A. V. Busuioc , D. Iftimie , M. C. Lopes Filho , H. J. Nussenzveig Lopes

We introduce the definition of conformable derivative on time scales and develop its calculus. Fundamental properties of the conformable derivative and integral on time scales are proved. Linear conformable differential equations with…

经典分析与常微分方程 · 数学 2018-01-09 Benaoumeur Bayour , Ahmed Hammoudi , Delfim F. M. Torres

We propose a generalized diffusion equation for a flat Euclidean space subjected to a continuous infinitesimal scale transform. For the special cases of an algebraic or exponential expansion/contraction, governed by time-dependent scale…

统计力学 · 物理学 2018-04-17 Manuel Schrauth , Maximilian Schneider

We define a symmetric derivative on an arbitrary nonempty closed subset of the real numbers and derive some of its properties. It is shown that real-valued functions defined on time scales that are neither delta nor nabla differentiable can…

经典分析与常微分方程 · 数学 2012-10-24 Artur M. C. Brito da Cruz , Natalia Martins , Delfim F. M. Torres

We construct a real-valued solution to the eigenvalue problem $-\text{div}(A\nabla u)=\lambda u$, $\lambda>0,$ in the cylinder $\mathbb{T}^2\times \mathbb{R}$ with a real, uniformly elliptic, and uniformly $C^1$ matrix $A$ such that…

偏微分方程分析 · 数学 2025-01-28 S. Krymskii , A. Logunov , F. Pagano

We prove new Hardy-type $\alpha$-conformable dynamic inequalities on time scales. Our results are proved by using Keller's chain rule, the integration by parts formula, and the dynamic H\"{o}lder inequality on time scales. When $\alpha=1$,…

综合数学 · 数学 2022-09-08 Ahmed A. El-Deeb , Samer D. Makharesh , Delfim F. M. Torres

We present an algorithm to calculate the linear response of periodic systems in the time-dependent density functional thoery, using a real-space representation of the electron wave functions and calculating the dynamics in real time. The…

凝聚态物理 · 物理学 2009-02-05 G. F. Bertsch , J. -I. Iwata , Angel Rubio , K. Yabana

Fractional calculus is a powerful and effective tool for modelling nonlinear systems. The M derivative is the generalization of alternative fractional derivative. This M derivative obey the properties of integer calculus. In this paper, we…

综合数学 · 数学 2019-03-29 V. Padmapriya , M. Kaliyappan

The eigenvalues and eigenfunctions of a linear {\alpha}^{2}-dynamo have been computed for different spatial distributions of an isotropic \alpha-effect. Oscillatory solutions are obtained when \alpha exhibits a sign change in the radial…

地球与行星天体物理 · 物理学 2012-08-08 A. Giesecke , F. Stefani , G. Gerbeth

We study several numerical discretization techniques for the one-space plus one-time dimensional Dirac equation, including finite difference and space-time finite element methods. Two finite difference schemes and several space-time finite…

数值分析 · 数学 2014-12-04 Robert Vaselaar , Hyun Lim , Jung-Han Kimn