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In this paper, we study the time-fractional diffusion equation on a metric star graph. The existence and uniqueness of the weak solution are investigated and the proof is based on eigenfunction expansions. Some priori estimates and…

Analysis of PDEs · Mathematics 2020-04-20 Vaibhav Mehandiratta , Mani Mehra , Gunter Leugering

This paper studies the existence and uniqueness of local weak solutions to the d-dimensional tropical climate model without thermal diffusion. We establish that, when $\alpha=\beta\geq1$, $\eta=0$, any initial data $(u_{0},v_{0})\in…

Analysis of PDEs · Mathematics 2020-12-25 Baoquan Yuan , Ying Zhang

A time-fractional Fokker-Planck initial-boundary value problem is considered, with differential operator $u_t-\nabla\cdot(\partial_t^{1-\alpha}\kappa_\alpha\nabla u-\textbf{F}\partial_t^{1-\alpha}u)$, where $0<\alpha <1$. The forcing…

Analysis of PDEs · Mathematics 2020-03-24 Kim-Ngan Le , William McLean , Martin Stynes

In this paper we investigate existence of solutions for the system: \begin{equation*} \left\{ \begin{array}{l} D^{\alpha}_tu=\textrm{div}(u \nabla p),\\ D^{\alpha}_tp=-(-\Delta)^{s}p+u^{2}, \end{array} \right. \end{equation*} in…

Analysis of PDEs · Mathematics 2021-06-24 Esther S. Daus , Maria Pia Gualdani , Jingjing Xu , Nicola Zamponi , Xinyu Zhang

We construct a theory of existence, uniqueness and regularity of solutions for the fractional heat equation $\partial_t u +(-\Delta)^s u=0$, $0<s<1$, posed in the whole space $\mathbb{R}^N$ with data in a class of locally bounded Radon…

Analysis of PDEs · Mathematics 2016-08-30 Matteo Bonforte , Yannick Sire , Juan Luis Vazquez

We investigate the heat equation with a time-dependent, anisotropic, and potentially singular diffusivity tensor. Since weak (in the Sobolev sense) or distributional solutions may not exist in this setting, we employ the framework of very…

Analysis of PDEs · Mathematics 2026-04-28 Zhirayr Avetisyan , Zahra Keyshams , Monire Mikaeili Nia , Michael Ruzhansky

We investigate the heat equation with a time-dependent, anisotropic, and potentially singular diffusivity tensor. Since weak (in the Sobolev sense) or distributional solutions may not exist in this setting, we employ the framework of very…

Analysis of PDEs · Mathematics 2025-07-22 Zhirayr Avetisyan , Zahra Keyshams , Monire Mikaeili Nia , Michael Ruzhansky

In this paper, we consider the fractional heat equation $u_{t}=\triangle^{\alpha/2}u+f(u)$ with Dirichlet boundary conditions on the ball $B_{R}\subset \mathbb{R}^{d}$, where $\triangle^{\alpha/2}$ is the fractional Laplacian,…

Analysis of PDEs · Mathematics 2016-06-08 Kexue Li

For a heat equation with Robin's boundary conditions which depends on a parameter $\alpha>0$, we prove that its unique weak solution $\rho^\alpha$ converges, when $\alpha$ goes to zero or to infinity, to the unique weak solution of the heat…

Probability · Mathematics 2013-03-26 Tertuliano Franco , Patricia Gonçalves , Adriana Neumann

This paper deals with initial value problems for fractional functional differential equations with bounded delay. The fractional derivative is defined in the Caputo sense. By using the Schauder fixed point theorem and the properties of the…

Classical Analysis and ODEs · Mathematics 2017-05-18 Chung-Sik Sin

In this manuscript we consider a non-local porous medium equation with non-local diffusion effects given by a fractional heat operator \begin{equation*} \partial_t u = \mbox{div}(u\nabla p),\qquad \partial_t p = -(-\Delta)^s p + u^2,…

Analysis of PDEs · Mathematics 2018-12-19 Esther S. Daus , Maria Gualdani , Nicola Zamponi

In this paper, we establish existence and uniqueness of weak solutions to general time fractional equations and give their probabilistic representations. We then derive sharp two-sided estimates for fundamental solutions of a family of time…

Probability · Mathematics 2017-09-12 Zhen-Qing Chen , Panki Kim , Takashi Kumagai , Jian Wang

A recent development in the theory of fractional differential equations with variable coefficients has been a method for obtaining an exact solution in the form of an infinite series involving nested fractional integral operators. This…

Classical Analysis and ODEs · Mathematics 2021-05-04 Arran Fernandez , Joel E. Restrepo , Durvudkhan Suragan

We study a time-fractional semilinear heat equation $$\partial^{\alpha}_t u -\Delta u = u^{p},\ \ \mbox{in}\ (0,T)\times\mathbb{R}^N,\ \ u(0)=u_0\ge0$$ with $u_0\in L^{1}(\mathbb{R}^N)$ and $p=1+2/N$. Here $\partial_t^{\alpha}$ denotes the…

Analysis of PDEs · Mathematics 2023-02-03 Mizuki Kojima

In this paper, we discuss the uniqueness for solution to time-fractional diffusion equation $\partial_t^\alpha (u-u_0) + Au=0$ with the homogeneous Dirichlet boundary condition, where an elliptic operator $-A$ is not necessarily symmetric.…

Analysis of PDEs · Mathematics 2021-03-03 Daijun Jiang , Zhiyuan Li , Matthieu Pauron , Masahiro Yamamoto

In this paper, we study the heat equation with an irregular spatially dependent thermal conductivity coefficient. We prove that it has a solution in an appropriate very weak sense. Moreover, the uniqueness result and consistency with the…

Analysis of PDEs · Mathematics 2023-02-21 Michael Ruzhansky , Mohammed Elamine Sebih , Niyaz Tokmagambetov

We study the forward self-similar solutions to the $2$D hypodissipative Navier-Stokes equation with fractional diffusion $(-\Delta)^\alpha$ for $\frac{1}{2}<\alpha<1$. We first show that for arbitrarily large $(1-2\alpha)$-homogeneous…

Analysis of PDEs · Mathematics 2026-03-16 Thomas Y. Hou , Peicong Song

This work is devoted to the study of the existence of at least one weak solution to nonlocal equations involving a general integro-differential operator of fractional type. As a special case, we derive an existence theorem for the…

Analysis of PDEs · Mathematics 2020-04-22 Giovanni Molica Bisci , Dušan D. Repovš

This paper is devoted to discussing the existence and uniqueness of weak solutions to time-fractional elliptic equations having time-dependent variable coefficients. To obtain the main result, our strategy is to combine the Galerkin method,…

Analysis of PDEs · Mathematics 2021-01-29 H. T. Tuan

In this paper, we consider the backward problem for fractional in time evolution equations $\partial_t^\alpha u(t)= A u(t)$ with the Caputo derivative of order $0<\alpha \le 1$, where $A$ is a self-adjoint and bounded above operator on a…

Analysis of PDEs · Mathematics 2022-11-30 S. E. Chorfi , L. Maniar , M. Yamamoto