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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…

Optimization and Control · Mathematics 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…

Numerical Analysis · Mathematics 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.…

General Mathematics · Mathematics 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…

Analysis of PDEs · Mathematics 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…

Classical Analysis and ODEs · Mathematics 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…

General Topology · Mathematics 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…

Analysis of PDEs · Mathematics 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…

Solar and Stellar Astrophysics · Physics 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…

Analysis of PDEs · Mathematics 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…

Classical Analysis and ODEs · Mathematics 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…

Analysis of PDEs · Mathematics 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…

Classical Analysis and ODEs · Mathematics 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…

Statistical Mechanics · Physics 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…

Classical Analysis and ODEs · Mathematics 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…

Analysis of PDEs · Mathematics 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 $\alpha=1$,…

General Mathematics · Mathematics 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…

Condensed Matter · Physics 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…

General Mathematics · Mathematics 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…

Earth and Planetary Astrophysics · Physics 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…

Numerical Analysis · Mathematics 2014-12-04 Robert Vaselaar , Hyun Lim , Jung-Han Kimn