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We prove optimal estimates for the decay in time of solutions to a rather general class of non-local in time subdiffusion equations in $\mathbb{R}^d$. An important special case is the time-fractional diffusion equation, which has seen much…

Analysis of PDEs · Mathematics 2014-03-10 Jukka Kemppainen , Juhana Siljander , Vicente Vergara , Rico Zacher

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 consider an initial-boundary value problem for $\partial_tu-\partial_t^{-\alpha}\nabla^2u=f(t)$, that is, for a fractional diffusion ($-1<\alpha<0$) or wave ($0<\alpha<1$) equation. A numerical solution is found by applying a…

Numerical Analysis · Mathematics 2016-02-02 Kassem Mustapha , William McLean

We are concerned in this paper with the degenerate fractional diffusion advection equations posed in bounded domains. Due to a suitable formulation, we show the existence of weak entropy solutions for measurable and bounded initial and…

Analysis of PDEs · Mathematics 2022-10-10 Gerardo Huaroto , Wladimir Neves

In this paper, we mainly introduce a general method to study the existence and uniqueness of solution of free boundary problems with partially degenerate diffusion.

Analysis of PDEs · Mathematics 2019-11-21 Siyu Liu , Mingxin Wang

In this work, we consider a FDE (fractional diffusion equation) $${}^C D_t^\alpha u(x,t)-a(t)\mathcal{L} u(x,t)=F(x,t)$$ with a time-dependent diffusion coefficient $a(t)$. For the direct problem, given an $a(t),$ we establish the…

Analysis of PDEs · Mathematics 2019-04-08 Zhidong Zhang

We consider the inverse problem of identification of degenerate diffusion coefficient of the form $x^\alpha a(x)$ in a one dimensional parabolic equation by some extra data. We first prove by energy methods the uniqueness and Lipschitz…

Analysis of PDEs · Mathematics 2021-12-15 Piermarco Cannarsa , Anna Doubova , Masahiro Yamamoto

This paper considers the Dirichlet problem $$ -\mathrm{div}(a\nabla u_a)=f \quad \hbox{on}\,\,\ D, \qquad u_a=0\quad \hbox{on}\,\,\partial D, $$ for a Lipschitz domain $D\subset \mathbb R^d$, where $a$ is a scalar diffusion function. For a…

Analysis of PDEs · Mathematics 2016-12-19 Andrea Bonito , Albert Cohen , Ronald DeVore , Guergana Petrova , Gerrit Welper

In this article, we consider the space-time Fractional (nonlocal) diffusion equation $$\partial_t^\beta u(t,x)={\mathtt{L}_D^{\alpha_1,\alpha_2}} u(t,x), \ \ t\geq 0, \ x\in D, $$ where $\partial_t^\beta$ is the Caputo fractional derivative…

Analysis of PDEs · Mathematics 2020-05-19 Ngartelbaye Guerngar , Erkan Nane , Süleyman Ulusoy , Hans Werner Van Wyk

We investigate the regularity of local weak solutions to evolution equations of the form \[…

Analysis of PDEs · Mathematics 2026-04-23 Pasquale Ambrosio , Simone Ciani , Giovanni Cupini

In this paper we prove the global in time well-posedness of the following non-local diffusion equation with $\alpha \in[0,2/3)$: $$ \partial_t u = {(-\triangle)^{-1}u} \triangle u + \alpha u^2, \quad u(t=0) = u_0. $$ The initial condition…

Analysis of PDEs · Mathematics 2016-02-22 Joachim Krieger , Robert M. Strain

We consider a generalized degenerate diffusion equation with a reaction term $u_t=[A(u)]_{xx}+f(u)$, where $A$ is a smooth function satisfying $A(0)=A'(0)=0$ and $A(u),\ A'(u),\ A''(u)>0$ for $u>0$, $f$ is of monostable type in $[0,s_1]$…

Analysis of PDEs · Mathematics 2025-06-24 Fang Li , Bendong Lou

We study a nonlocal aggregation equation with degenerate diffusion, set in a periodic domain. This equation represents the generalization to $m > 1$ of the McKean-Vlasov equation where here the "diffusive" portion of the dynamics are…

Analysis of PDEs · Mathematics 2012-04-19 Lincoln Chayes , Inwon Kim , Yao Yao

In this work, a time-fractional nonlocal diffusion equation is considered. Based on the $L2$-$1_{\sigma}$ scheme on a graded mesh in time and the standard finite element method (FEM) in space, the fully-discrete $L2$-$1_{\sigma}$ finite…

Numerical Analysis · Mathematics 2023-06-06 Pari J. Kundaliya

We develop a unified and easy to use framework to study robust fully discrete numerical methods for nonlinear degenerate diffusion equations $$ \partial_t u-\mathfrak{L}^{\sigma,\mu}[\varphi(u)]=f \quad\quad\text{in}\quad\quad…

Numerical Analysis · Mathematics 2019-06-20 Félix del Teso , Jørgen Endal , Espen R. Jakobsen

In this paper, we use local fraction derivative to show the H\"older continuity of the solution to the following nonlinear time-fractional slow and fast diffusion equation:…

Probability · Mathematics 2021-05-04 Le Chen , Guannan Hu

We study solution techniques for an evolution equation involving second order derivative in time and the spectral fractional powers, of order $s \in (0,1)$, of symmetric, coercive, linear, elliptic, second-order operators in bounded domains…

Numerical Analysis · Mathematics 2018-06-18 Lehel Banjai , Enrique Otarola

This paper focuses on a nonlinear convection-diffusion equation with space and time-fractional Laplacian operators of orders $1<\beta<2$ and $0<\alpha\leq1$, respectively. We develop local discontinuous Galerkin methods, including Legendre…

Numerical Analysis · Mathematics 2026-02-11 Majid Rajabzadeh , Moein Khalighi

We study the long-time asymptotics of prototypical non-linear diffusion equations. Specifically, we consider the case of a non-degenerate diffusivity function that is a (non-negative) polynomial of the dependent variable of the problem. We…

Analysis of PDEs · Mathematics 2020-08-13 Ivan C. Christov , Akif Ibraguimov , Rahnuma Islam

We present an approach to handle Dirichlet type nonlocal boundary conditions for nonlocal diffusion models with a finite range of nonlocal interactions. Our approach utilizes a linear extrapolation of prescribed boundary data. A novelty is,…

Analysis of PDEs · Mathematics 2021-08-27 Hwi Lee , Qiang Du