English
Related papers

Related papers: Diffusion equations with general nonlocal time and…

200 papers

We propose diffusion-like equations with time and space fractional derivatives of the distributed order for the kinetic description of anomalous diffusion and relaxation phenomena, whose diffusion exponent varies with time and which,…

Statistical Mechanics · Physics 2009-11-07 A. V. Chechkin , R. Gorenflo , I. M. Sokolov

Space-time fractional evolution equations are a powerful tool to model diffusion displaying space-time heterogeneity. We prove existence, uniqueness and stochastic representation of classical solutions for an extension of Caputo evolution…

Analysis of PDEs · Mathematics 2018-09-03 Lorenzo Toniazzi

Functional limit theorem for continuous-time random walks (CTRW) are found in general case of dependent waiting times and jump sizes that are also position dependent. The limiting anomalous diffusion is described in terms of fractional…

Probability · Mathematics 2022-05-03 Vassili N. Kolokoltsov

We consider a Cauchy problem for the inhomogeneous differential equation given in terms of an unbounded linear operator $A$ and the Caputo fractional derivative of order $\alpha \in (0, 2)$ in time. The previously known representation of…

Numerical Analysis · Mathematics 2025-04-10 Dmytro Sytnyk , Barbara Wohlmuth

We investigate the qualitative behavior of the initial traces of nonnegative solutions to the fast diffusion equation with power-type nonlinearity. Necessary conditions for the existence of solutions to the corresponding Cauchy problem are…

Analysis of PDEs · Mathematics 2025-10-01 Kazuhiro Ishige , Nobuhito Miyake

Fractional diffusion and Fokker-Planck equations are widely used tools to describe anomalous diffusion in a large variety of complex systems. The equivalent formulations in terms of Caputo or Riemann-Liouville fractional derivatives can be…

Statistical Mechanics · Physics 2023-08-17 Qing Wei , Wei Wang , Hongwei Zhou , Ralf Metzler , Aleksei Chechkin

In the paper, the initial-boundary value problems to a semilinear integro-differential equation with multi-term fractional Caputo derivatives are analyzed. A particular case of this equation models oxygen diffusion through capillaries.…

Analysis of PDEs · Mathematics 2024-03-05 Nataliya Vasylyeva

Given a connected compact Riemannian manifold $(M,g)$ without boundary, $\dim M\ge 2$, we consider a space--time fractional diffusion equation with an interior source that is supported on an open subset $V$ of the manifold. The…

Analysis of PDEs · Mathematics 2019-03-12 Tapio Helin , Matti Lassas , Lauri Ylinen , Zhidong Zhang

In this paper we obtain new estimates of the sequential Caputo fractional derivatives of a function at its extremum points. We derive comparison principles for the linear fractional differential equations, and apply these principles to…

Analysis of PDEs · Mathematics 2021-06-15 Mokhtar Kirane , Berikbol T. Torebek

We consider a continuous random walk model for describing normal as well as anomalous diffusion of particles subjected to an external force when these particles diffuse in a uniformly expanding (or contracting) medium. A general equation…

Statistical Mechanics · Physics 2018-10-17 F. Le Vot , S. B. Yuste

We establish trace and extension theorems for evolutionary equations with the Caputo fractional derivatives in (weighted) $L_p$ spaces. To achieve this, we identify weighted Sobolev and Besov spaces with mixed norms that accommodate…

Analysis of PDEs · Mathematics 2023-08-28 Doyoon Kim , Kwan Woo

We formulate the generalized master equation for a class of continuous time random walks in the presence of a prescribed deterministic evolution between successive transitions. This formulation is exemplified by means of an…

Statistical Mechanics · Physics 2009-11-13 S. Eule , R. Friedrich , F. Jenko , I. M. Sokolov

In this work we investigate an inverse problem of identifying a spatially variable order in the one-dimensional subdiffusion model from the boundary flux measurement. The model involves a generalized Caputo derivative in time, and arises in…

Analysis of PDEs · Mathematics 2024-11-28 Jiho Hong , Bangti Jin , Yavar Kian

Continuous Time Random Walks (CTRWs) are jump processes with random waiting times between jumps. We study scaling limits for CTRWs where the distribution of jumps and waiting times is coupled and varies in space and time. Such processes…

Probability · Mathematics 2015-01-06 Peter Straka

In this paper, we study the Cauchy problem to the 3D fractional compressible isentropic generalized Navier-Stokes equations for viscous compressible fluid with one Levy diffusion process. We obtain the existence and uniqueness of global…

Analysis of PDEs · Mathematics 2024-07-03 Mengqian Liu , Lei Niu , Zhigang Wu

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 strong dissipativity of generalized time-fractional derivatives on Gelfand triples of properly in time weighted $L^p$-path spaces is proved. In particular, the classical Caputo derivative is included as a special case. As a…

Analysis of PDEs · Mathematics 2021-02-23 Wei Liu , Michael Röckner , José Luís da Silva

We consider the highly nonlinear and ill-posed inverse problem of determining some general expression $F(x,t,u,\nabla_xu)$ appearing in the diffusion equation $\partial_tu-\Delta_x u+F(x,t,u,\nabla_xu)=0$ on $\Omega\times(0,T)$, with $T>0$…

Analysis of PDEs · Mathematics 2019-03-13 Pedro Caro , Yavar Kian

A distributed order fractional diffusion equation is considered. Distributed order derivatives are fractional derivatives that have been integrated over the order of the derivative within a given range. In this paper sub-diffusive cases are…

Mathematical Physics · Physics 2007-05-23 Mark Naber

We investigate diffusion equations with time-fractional derivatives of space-dependent variable order. We examine the well-posedness issue and prove that the space-dependent variable order coefficient is uniquely determined among other…

Analysis of PDEs · Mathematics 2018-12-05 Yavar Kian , Eric Soccorsi , Masahiro Yamamoto