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We examine initial-boundary value problems for diffusion equations with distributed order time-fractional derivatives. We prove existence and uniqueness results for the weak solution to these systems, together with its continuous dependency…

Analysis of PDEs · Mathematics 2017-09-21 Zhiyuan Li , Yavar Kian , Eric Soccorsi

We use the hyperbolic subdiffusion equation with fractional time derivatives (the generalized Cattaneo equation) to study the transport process of electrolytes in media where subdiffusion occurs. In this model the flux is delayed in a…

Statistical Mechanics · Physics 2009-11-13 Tadeusz Kosztolowicz , Katarzyna D. Lewandowska

This paper is devoted to the study of the inverse problem of determining the right-hand side of the subdiffusion equation with the Caputo derivative with respect to time. In our case, the inverse problem consists in restoring the…

Analysis of PDEs · Mathematics 2025-05-20 R. R. Ashurov , O. T. Mukhiddinova

In this paper, we investigate a nonlinear inverse problem aimed at recovering a coefficient $a(t, x)$, dependent on both time and a subset of spatial variables, in a diffusion equation \( u_t - \Delta_x u - u_{yy} +a(t, x) u = f(t,x,y) \),…

Analysis of PDEs · Mathematics 2025-08-07 R. R. Ashurov , O. T. Mukhiddinova

In this paper, we investigate the inverse problem of determining the right-hand side of a subdiffusion equation with a Caputo time derivative, where the right-hand side depends on both time and certain spatial variables. Similar inverse…

Analysis of PDEs · Mathematics 2025-05-08 R. R. Ashurov , O. T. Mukhiddinova

The behaviour of the solutions of the time-fractional diffusion equation, based on the Caputo derivative, is studied and its dependence on the fractional exponent is analysed. The time-fractional convection-diffusion equation is also solved…

Mathematical Physics · Physics 2024-10-14 Andy Manapany , Sébastien Fumeron , Malte Henkel

We derive explicit solutions for time-fractional anomalous diffusion equations with diffusivity coefficients that depend on both space and time variables. These solutions are expressed in Fox-H and generalized Wright functions, which are…

Analysis of PDEs · Mathematics 2024-05-14 Ganbileg Bat-Ochir , Khongorzul Dorjgotov , Uuganbayar Zunderiya

In this paper we investigate the variable coefficient two-sided fractional diffusion, advection, reaction equations on a bounded interval. It is known that the fractional diffusion operator may lose coercivity due to the variable…

Numerical Analysis · Mathematics 2022-03-23 Xiangcheng Zheng , V. J. Ervin , Hong Wang

We derive a fundamental solution $\mathscr{E}$ to a space-fractional diffusion problem on the half-line. The equation involves the Caputo derivative. We establish properties of $\mathscr{E}$ as well as formulas for solutions to the…

Analysis of PDEs · Mathematics 2021-11-03 Tokinaga Namba , Piotr Rybka , Shoichi Sato

In this work, we study a new spectral Petrov-Galerkin approximation of space-time fractional reaction-diffusion equations with viscosity terms built by Riemann-Liouville fractional-order derivatives. The proposed method is reliant on…

Numerical Analysis · Mathematics 2019-11-26 Zhe Yu , Boying Wu , Jiebao Sun , Wenjie Liu

We study a linear-quadratic optimal control problem involving a parabolic equation with fractional diffusion and Caputo fractional time derivative of orders $s \in (0,1)$ and $\gamma \in (0,1]$, respectively. The spatial fractional…

Optimization and Control · Mathematics 2015-04-02 Harbir Antil , Enrique Otarola , Abner J. Salgado

We derive optimal $L^2$-error estimates for semilinear time-fractional subdiffusion problems involving Caputo derivatives in time of order $\alpha\in (0,1)$, for cases with smooth and nonsmooth initial data. A general framework is…

Numerical Analysis · Mathematics 2020-04-28 Samir Karaa

This paper is concerned with the fractional evolution equation with a discrete distribution of Caputo time-derivatives such that the largest and the smallest orders, $\alpha$ and $\alpha_m$, satisfy the conditions $1<\alpha\le 2$ and…

Analysis of PDEs · Mathematics 2018-01-11 Emilia Bazhlekova , Ivan Bazhlekov

In this paper, we focus on a space-time fractional diffusion equation with the generalized Caputo's fractional derivative operator and a general space nonlocal operator (with the fractional Laplace operator as a special case). A weak…

Analysis of PDEs · Mathematics 2016-06-07 Junxiong Jia , Jigen Peng , Jiaqing Yang

Time-space fractional Bloch-Torrey equations (TSFBTEs) are developed by some researchers to investigate the relationship between diffusion and fractional-order dynamics. In this paper, we first propose a second-order implicit difference…

Numerical Analysis · Mathematics 2023-08-31 Yong-Liang Zhao , Xian-Ming Gu , Hu Li

We investigate global uniqueness for an inverse problem for a nonlocal diffusion equation on domains that are bounded in one direction. The coefficients are assumed to be unknown and isotropic on the entire space. We first show that the…

Analysis of PDEs · Mathematics 2022-11-16 Yi-Hsuan Lin , Jesse Railo , Philipp Zimmermann

In this article, we are concerned with the analysis on the numerical reconstruction of the spatial component in the source term of a time-fractional diffusion equation. This ill-posed problem is solved through a stabilized nonlinear…

Numerical Analysis · Mathematics 2020-05-06 Daijun Jiang , Yikan Liu , Dongling Wang

The present paper is devoted to constructing L2 type difference analog of the Caputo fractional derivative. The fundamental features of this difference operator are studied and it is used to construct difference schemes generating…

Numerical Analysis · Mathematics 2021-02-18 Anatoly A. Alikhanov , Chengming Huang

In the present paper, we study the Cauchy-Dirichlet problem to the nonlocal nonlinear diffusion equation with polynomial nonlinearities $$\mathcal{D}_{0|t}^{\alpha…

Analysis of PDEs · Mathematics 2022-11-28 Meiirkhan B. Borikhanov , Michael Ruzhansky , Berikbol T. Torebek

In this paper, we study a linear convection-diffusion equation with time-dependent coefficients on a bounded interval. The problem includes inhomogeneous Dirichlet boundary conditions and is motivated by physical models where the…

Analysis of PDEs · Mathematics 2025-10-22 Konstantinos Kalimeris , Türker Özsarı
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