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We start with a general governing equation for diffusion transport, written in a conserved form, in which the phenomenological flux laws can be constructed in a number of alternative ways. We pay particular attention to flux laws that can…

Analysis of PDEs · Mathematics 2019-02-22 Tokinaga Namba , Piotr Rybka , Vaughan Voller

Historically the fractional calculus concept works an extended idea based on the question asked by Guillaume de L'H\^opital to Gottfried Wilhelm Leibniz in 1695 about the notation ${d^nf}/{dx^n}$ for the derivative operator "What if…

Mathematical Physics · Physics 2025-07-08 J. J. A. de Oliveira , C. F. L. Godinho

In mathematical modeling of the non-squared frequency-dependent diffusions, also known as the anomalous diffusions, it is desirable to have a positive real Fourier transform for the time derivative of arbitrary fractional or odd integer…

Computational Engineering, Finance, and Science · Computer Science 2007-05-23 W Chen

Integer-order differential operators were originally used to describe local and isotropic effects, in both space and time. However, in fields like biology, the modelling of complex phenomena with spatial heterogeneity necessitates more…

Dynamical Systems · Mathematics 2025-03-18 Cypres Verbeeck , Nikolaos Sfakianakis

Initialization of fractional differential equations remains an ongoing problem. In recent years, the initialization function approach and the infinite state approach provide two effective ways to deal with this problem. The purpose of this…

General Mathematics · Mathematics 2018-11-29 Jian Yuan , Guozhong Xiu , Bao Shi

In this article we solve the Cauchy problem for the relaxation equation posed in a framework of variable order fractional calculus. After introducing some general mathematical theory we establish concepts of Scarpi derivative and transition…

General Mathematics · Mathematics 2026-05-28 Matija Adam Horvat , Nikola Sarajlija

This book intends to deepen the study of the fractional calculus, giving special emphasis to variable-order operators. It is organized in two parts, as follows. In the first part, we review the basic concepts of fractional calculus (Chapter…

Optimization and Control · Mathematics 2018-06-19 Ricardo Almeida , Dina Tavares , Delfim F. M. Torres

The time-fractional diffusion-wave equation is revisited, where the time derivative is of order $2 \nu$ and $0 < \nu \le 1$. The behaviour of the equation is "diffusion-like" (respectively, "wave-like") when $0 < \nu \le \frac{1}{2}$…

Analysis of PDEs · Mathematics 2021-10-25 Marianito R. Rodrigo

Based on the continuous time random walk, we derive the Fokker-Planck equations with Caputo-Fabrizio fractional derivative, which can effectively model a variety of physical phenomena, especially, the material heterogeneities and structures…

Numerical Analysis · Mathematics 2020-08-24 Minghua Chen , Jiankang Shi , Weihua Deng

We formulate fractional difference equations of Riemann-Liouville and Caputo type in a functional analytical framework. Main results are existence of solutions on Hilbert space-valued weighted sequence spaces and a condition for stability…

Two approximations, derived from continuous expansions of Riemann-Liouville fractional derivatives into series involving integer order derivatives, are studied. Using those series, one can formally transform any problem that contains…

Optimization and Control · Mathematics 2013-05-10 Shakoor Pooseh , Ricardo Almeida , Delfim F. M. Torres

In this note we analyse the propagation of a small density perturbation in a one-dimensional compressible fluid by means of fractional calculus modelling, replacing thus the ordinary time derivative with the Caputo fractional derivative in…

Analysis of PDEs · Mathematics 2014-03-06 Roberto Garra , Federico Polito

We introduce a fractional calculus on time scales using the theory of delta (or nabla) dynamic equations. The basic notions of fractional order integral and fractional order derivative on an arbitrary time scale are proposed, using the…

Classical Analysis and ODEs · Mathematics 2010-12-08 Nuno R. O. Bastos , Dorota Mozyrska , Delfim F. M. Torres

We prove existence of solutions for a nonlinear fractional oscillator equation with both left Riemann-Liouville and right Caputo fractional derivatives subject to natural boundary conditions. The proof is based on a transformation of the…

Classical Analysis and ODEs · Mathematics 2017-06-12 Assia Guezane-Lakoud , Rabah Khaldi , Delfim F. M. Torres

Discrete maps with long-term memory are obtained from nonlinear differential equations with Riemann-Liouville and Caputo fractional derivatives. These maps are generalizations of the well-known universal map. The memory means that their…

Chaotic Dynamics · Physics 2015-03-17 Vasily E. Tarasov

Spatial non-locality of space-fractional viscoelastic equations of motion is studied. Relaxation effects are accounted for by replacing second-order time derivatives by lower-order fractional derivatives and their generalizations. It is…

Mathematical Physics · Physics 2015-06-03 Andrzej Hanyga , Malgorzata Seredynska

An adaptive finite difference scheme for variable-order fractional-time subdiffusion equations in the Caputo form is studied. The fractional time derivative is discretized by the L1 procedure but using nonhomogeneous timesteps. The size of…

Numerical Analysis · Mathematics 2024-09-20 Joaquín Quintana-Murillo , Santos Bravo Yuste

Taylor series is a useful mathematical tool when describing and constructing a function. With the series representation, some properties of fractional calculus can be revealed clearly. This paper investigates two typical applications:…

General Mathematics · Mathematics 2020-02-18 Yiheng Wei , Da-Yan Liu , Peter W. Tse , Yong Wang

In recent years, the use of variable-order differential operators has emerged as a powerful tool in the analysis of nonlinear fractional differential equations and chaotic systems. In finance, the accurate prediction of market trends and…

Dynamical Systems · Mathematics 2023-07-10 Shahariar Ryehan

We propose a probabilistic construction for the solution of a general class of fractional high order heat-type equations in the one-dimensional case, by using a sequence of random walks in the complex plane with a suitable scaling. A time…

Probability · Mathematics 2017-10-11 Stefano Bonaccorsi , Mirko D'Ovidio , Sonia Mazzucchi